(Internet slang, especially anime and manga fandom) events or things from the past which one wants to whitewash/erase from history (due to it being embarrassing, poorly received, etc.); dark past

study of history

historic, historical / already-happened, past / former, old, traditional

Alternative form of 逢引

Synonym of 干満 (“ebb and flow”)

(informal) to be at a loss for words

(informal) at a loss for words

Alternative spelling of 引きこもり: hikikomori

pimp

(poetic) a pillow word of uncertain meaning: allusion to 山 (yama, “mountain”) or words beginning with yama