Bitter (adjective)

1. Having a harsh, disagreeable taste, like that of wormwood or aloes.
2. Having a sharp or acrid taste like that of unsweetened cocoa or strong coffee.
3. Having a sharp, pungent taste or smell.
4. Unpleasantly or sharply disagreeable or painful.

Origin:

Old english biter, of germanic origin; related to dutch bitter and german bitter.

Examples:

1. The medicine was bitter.
2. She had a bitter expression on her face.
3. The coffee was too bitter for me.
4. He had a bitter disappointment.
5. The cold wind was bitter.