mučno

1. (mučno je + dat.) sick; nauseous
   Mučno mi je od vožnje autobusom. — The bus ride is making me feel sick.
2. (of a situation) distressing; painful
   Bilo je mučno gledati kako pati. — It was painful to watch him suffer.
   Na sastanku je vladala mučna tišina, svima je bilo mučno. — There was an awkward silence at the meeting; everyone felt uneasy.
3. with difficulty; painfully
   Starac se mučno popeo uz stepenice. — The old man struggled up the stairs.

The person affected goes in the dative: mučno mi je "I feel sick / uneasy".