cruel and unfair

an oppressive government/military regime 暴虐的政府／军事政权

causing people to feel worried and uncomfortable

an oppressive silence 令人难耐的静寂

If the weather or heat is oppressive, it is too hot and there is no wind.

We were unable to sleep because of the oppressive heat. 天气闷热得令人窒息，我们难以入睡。