nothing, nothingness / (Buddhism) mu; the null set: neither yes nor no (in response to a koan or other question that mistakenly assumes an affirmative or negative answer).

夕方: early evening

階級: class, rank, grade / 懐旧: recalling the old days, nostalgia, reminiscences

time / an event, case, occasion, moment; a specific period in time / a time of something / a season / a tense / (literary) the time during which a narrative takes place

break

break

(originally Kyūshū) Synonym of こい (koi, “deep; strong; dense”)

non-, un- / non-, un-

固有関数: eigenfunction

(Internet slang, humorous) I don't know why, but I can't convert it [this hiragana] into kanji [using my IME]