Bitter

Bitter is the name given to one of the four basic tastes. The other three are sour, sweet, and salt. It is sharp. pungent, harsh, and disagreeable in taste or smell. Anything having this test is referred to as bitter. A beer strongly flavoured with hops is also called bitter, because it tastes bitter. However, 'bitters' denote liquors flavoured by or made of bitter plants, which are sometimes used as medicines.

It also refers to a range of human feelings such as acrimony, anger, resentment, or extreme unpleasantness that arise in someone when they are hurt by someone or something. It can also arise from opposition, argument, conflict, or weather conditions etc.