Oppressive

adjective

1. Burdensome or difficult to bear.

   "The oppressive tax laws made it difficult to start a small company."

2. Tyrannical or exercising unjust power.

   "The oppressive land-owners kept a grip on the labourers."

3. Weighing heavily on the spirit; intense, or overwhelming

   "Will the oppressive heat of summer never end?"

4. Hot and humid of the weather.