onerous (adjective) onerous: difficult; requiring hard labor
Sinonime: bitter,
depressing,
disagreeable, disconcerting, discouraging, disheartening, displeasing,
distasteful,
failing, falling short, frustrating, inadequate,
ineffective,
inferior, insufficient, lame, mediocre, unfulfilling,
unhappy, uninteresting,
unpleasant, unsatisfying
Antonime: encouraging,
pleasing,
satisfactory