In Japanese, yoku よ, also spelled yoku 良く, means literally that you've done "good" or have done "well," but it can also mean something happens "often" or "a lot," and it can also mean something is "impressive" to have done, often given unfavorable circumstances, or, also, because of the nerve you had to have to dare do it.

The word yoku よく is the adverbial form of ii いい, or rather, of yoi 良い. Note that yokunai よくない means "not good" instead, because to inflect the negative form of i-adjectives you add the auxiliary nai ない to the adverbial form. And yokute よくて is the te-form of the i-adjective.

• "To Do Well"
  • よくやった
  • よく頑張った
  • よく出来た
  • よく聞け
  • よく見ると
• よくそんな
  • "Hard to Believe You Did That"
  • "Ugh! I Would Never Do That!!! Don't You Have No Shame?!"
  • "You Peasant, Don't You Know Your Place?!"
• "Often"
  • "A lot"
• Expressions
• Grammar
• 良く, 善く, 能く, 好く, 克く

In Japanese, yokunai よくない, "not good," also spelled yokunai 良くない, is the negative form of ii いい, "good."

Fortunately, there isn't much special about it. It's just the negative of ii いい.

The word yokunakatta よくなかった would be "was not good," past negative. Technically, both yokunai and yokunakatta are inflections of the i-adjective yoi よい, not of ii いい, but ii is never inflected, ii and yoi are synonymous, and ii is more common, so they're de facto inflections of ii.

• "Not Good"
  • Yokunai vs Warui
• Yokunee よくねー, 良くねぇ, よくねー, 良くねぇ

In Japanese, warukunai 悪くない means literally "not bad," the negative form of warui 悪い, "bad." The word warukunai can also mean "it's not my fault" or "it's not his fault," since warui can be used to say something is something's fault. For the same reason, warukunai can also mean there's nothing "wrong" with something.

The word warukunakatta 悪くなかった, "was not bad," past negative form, would also work similarly but in the past.

• "Not Bad"
• "Not My Fault"
• "Nothing Wrong With This"

In Japanese, yokatta よかった means "was good," "I'm glad," "that's a relief," "thank goodness," and "it would have been better [if...]," depending on context.

It's the past form of ii いい. Its antonym is warukatta 悪かった.

• Kanji
• Grammar
  • "Was Good"
    • "I'm Glad"
    • "That's a Relief"
    • "Thank Goodness"
  • よかったじゃない？
  • ~てよかった
    • ～でよかった
  • Counterfactuals
    • ～ばよかった
    • ～ならよかった
    • ～方がよかった
    • するんじゃなかった

In Japanese, hou ga ii 方がいい means "it's better if" most of the time. It can be used in three ways: to advise to do something, to warn them to not do something, or to simply state you think it would be better if something happened or not.

A variant is hou ga yoi 方がよい. It's also spelled hou ga ii/yoi 方が良い, ほうがいい, ほうがよい.

• Examples
  • It's better if... something didn't happen
  • It's better if... you don't do something
  • It's better if... you do something
• Explanation
• Hou ga Yokatta 方がよかった

In Japanese, warukatta 悪かった often means "sorry for that" or "it was his fault," although, literally, warukatta means "was bad." It's the past form of the i-adjective warui 悪い, "bad," which can used to say "sorry" and blame people for things.

• Examples

In Japanese, warii 悪ぃ means "sorry" or "my bad" most of the time. It's also spelled 悪ィ, わりぃ, ワリィ, etc. It's a relaxed pronunciation of warui 悪い, so everything warui means warii means too.

• Nuance
• Spelling
• Examples
  • 悪ィ
  • ワリぃ
  • ワリィワリィ

The phrase warui slime janai yo, or rather, warui suraimu janai yo 悪いスライムじゃないよ, meaning "[I'm] not a bad slime," comes from the RPG series Dragon Quest: it's a catch-phrase used used by NPC slimes to tell the player they aren't going to fight him.

• Tensei Shitara Slime Datta Ken
• Origin

In Japanese, meaning of warui 悪い would be literally "bad." It's an i-adjective. Note, however, that a lot of times warui and its inflections have other meanings and usage, like to say "sorry," to say somebody is at "fault," to ask what's "wrong" about something, and so on.

Since it can be pretty hard to tell which meaning exactly you're facing in any given phrase, I recommend you to read the whole article to familiarize yourself with all the ways warui can be used, rather than just reading a few sections.

• Basic Usage
• Conjugation
• Antonym
  • Negative Antonym
• "Sorry"
• Warii 悪ぃ【わりぃ】
• It's Your "Fault"
• Warukatta 悪かった
• That Was a "Mistake"
• Warukunai 悪くない
• "Wrong"
• Warui Kedo 悪いけど
• Niwa Warui Kedo には悪いけど
• Waruku 悪く
• Warusa 悪さ
• Set Phrases
  • Warui Hito 悪い人
  • Warui Koto 悪いこと
  • -ga Warui ～が悪い
• Other Words That Mean "Bad"

In Japanese, doshigatai 度し難い means "irredeemable," "beyond salvation." However, the literal meaning of the word a bit more complicated. And given that this is a catchphrase in the manga and anime Made in Abyss, I supposed it deserves a thorough explanation.

In Japanese, ~gatai ～がたい, also spelled ~gatai ～難い, is an auxiliary adjective that means something "hard to do" because you aren't willing to do it, or it's "hard to happen" because you don't believe it normally happen.

(not to be confused with gattai 合体, which means "to combine.")

• Usage
• Conjugation
• ～難い
  • Katai 難い
• ～がたい vs. ～にくい
  • Resisting to Do It
  • I'd Rather Not
  • Psychological Verbs
  • Probably Not Gonna Happen
• ～がたい vs. ～づらい
• Further Reading

In Japanese, ~dzurai ～づらい, also written ~dzurai ～辛い, pronounced the same way as zurai ずらい, and inputted in an IME as durai, is an auxiliary adjective that means a verb is "hard for you to do" because doing it causes you trouble or distress.

• Usage
• Conjugation
• tsurai 辛い
• zurai ずらい
• ～づらい vs. ～にくい
• Antonym
• Further Reading

In Japanese, -nikui ～にくい, also written -nikui ～難い, -nikui ～悪い, is an auxiliary adjective that means something is "hard to do." In essence, -nikui ～にくい is the antonym of the auxiliary adjective -yasui ～やすい, which means "easy to do."

• Usage
• Conjugation
• Homonyms
  • Nikui 憎い
  • Minikui 醜い vs. 見にくい
  • -gatai ～難い
• "Hard" in Japanese
  • "Hard" Difficulty
  • "Hardware"
  • "Hard," i.e. "Not Soft"
• Examples
  • 息がしにくい
• Further Reading

In Japanese, ~yasui ～やすい is an auxiliary adjective that means something is "easy" to do or to happen. It's also a normal i-adjective that means "easy," yasui 易い. When the word is written with a different kanji, yasui 安い, it means something is "cheap" or "calm."

• Auxiliary Adjective
  • Usage
  • Conjugation
  • Easy to Do vs. Easy to Happen
• 易い
  • Tayasui たやすい【容易い】
• 安い
  • "Cheap"
  • "Calm"
    • 安らか、安らかな
• Antonyms
  
• "Easy" in Japanese
  • Easy Game Difficulty
  • Easy Woman
• Examples
  • 分かりやすい
  • 気安い
• Further Reading

In Japanese, -rashii ～らしい is an auxiliary adjective that has a couple of tricky meanings. Usually, rashii means "I heard that," or "it seems that," or "it's like that," or "-esque," depending on how it's used.

• Definition
• Rumors & Hearsay
• お前らしい
  • らしくない
  • らしくなった
• Fitting The Role
  • Acting The Role
• -esque
• -ish
• -ly
  • 可愛らしい vs. 可愛いらしい
• らしく Conjectures
• らしい vs. ようだ
• Further Reading