In Japanese, kakkoii かっこいい means "good-looking." It's generally used toward things and people who "look good," in various ways, such as looking "cool," "impressive," "stylish," "fashionable," "admirable," and so on.
Variants of the word include: kakkoii カッコイイ, kakko-ii カッコいい, かっこ良い, kakko-yoi かっこよい, kakkou-ii 格好いい, 格好良い, kakkou-yoi 格好よい, and kakkee かっけえ, かっけぇ, かっけー.
In Japanese, kakkowarui かっこ悪い means "lame." It's used when someone, something they wear, or something they do, is "uncool," or "un-stylish," "or un-fashioable", or leaves a bad impression in general. Variants include kakko-warui カッコ悪い, kakko-warii かっこワリぃ, and kakkou-warui 格好悪い.
In Japanese, goshujinsama ご主人様 means the "master" of a servant, in anime, mostly of a maid. The word may also refer to the "owner" of a house or shop, to one's "husband," or to a pet's "owner."
In Japanese, ossan おっさん means "old man," or "middle-aged man." This isn't a polite word, so it's either used to refer to an old man in a cozy, friendly way, or in a rude, derogatory way. It's also spelled ossan オッサン, オッさん.
In Japanese, oneesan お姉さん means "older sister," and sometimes refers to a young girl. It's also romanized onēsan, with a macron for the long vowel.
The younger counterpart is imouto 妹, "young sister." The male counterparts are oniisan お兄さん and otouto 弟, "older brother" and "younger brother," respectively.
In Japanese, oniisan お兄さん means "older brother," and sometimes refers to a young man. It's also romanized onīsan, with a macron for the long vowel.
The younger counterpart is otouto 弟, "young brother." The female counterparts are oneesan お姉さん and imouto 妹, "older sister" and "younger sister," respectively.
In Japanese, zoku 続 means "sequel," or more literally, "continuation." It's found in the names of some anime which refer to the second season of a series or some other sort of continuation.
It's spelled with the same kanji as tsuduku 続く, which means "to continue" and is sometimes found at the end of an episode (typically spelled with hiragana, as tsuduku つづく) because the series continues in the next episode.
In Japanese, oni 鬼 is a kind of "supernatural being," youkai 妖怪 in Japan's culture, often translated to English as "ogre" or "troll," although those would be technically different things. Generally speaking, an oni in anime is a big, strong, scary, evil, rugged, powerful humanoid monster, who has one or two horns on its head, fangs, and the like, but designs may vary. Thematically, humans are said to be afraid of oni because oni are said to devour humans, they're generally brutes or savages, and there's a well-known story about a blue and a red oni who try to become friends with humans through some sacrifice to make them be not afraid.
Not to be confused with oniisan お兄さん, which means "older brother."
Nowadays, oni are normally portrayed featuring colored skin, specially red and blue, just like the modern day ogre is usually green. In anime, oni characters can usually talk and have some sort of connection with the demon world, afterlife, hell, makai 魔界, or something supernatural like that.
Apparently, the word oni would mean it's an invisible spirit, originally, but that's rarely the case in modern fiction.
