いやな (translations)→ awful bad bilious dirty disagreeable dismal disturbingly dreadful frightful harsh leprous lousy noisome odious ominously paralytic queasy shitty terrifying troubled unloved unwanted wicked
つまらない (translations)→ bleak disappoint disgusting fool foolish fucking futile goddam horrible inadequate intolerable menial pedantic peewee prosaic rubbishy tedious unexciting uninteresting unreadable wearisome wretched zilch
つまんない (translations)→ bore stupid
ほんとうに (translations)→ absolutely actually adventure all genuinely honestly how just particularly perfectly pretty quite rather real really seriously sheer so terribly totally yes
退屈 (translations)→ bored boredom dull time uneventful
退屈な (translations)→ enduring irksome poor prasaic tiring unlively