I-adjective (keiyoushi)

difficult; hard; troublesome; complicated; serious (disease, problem, etc.)

impossible; unfeasible

Euphemisticsofter than 無理

fussy; particular; fastidious; hard to please; displeased

gloomy; glum; sullen; serious (look)

dirty; unclean; filthy; detestable

Archaic

unpleasant; uncomfortable; creepy; spooky

Archaic