ETYM AS. biter; akin to Goth. baitrs, Icel. bitr, Dan., Swed., Dutch, and German bitter, OS. bittar, from root of Eng. bite. Related to Bite.
1. Expressive of severe grief or regret.
2. One of the four basic taste sensations; sharp and disagreeable; like the taste of quinine.
3. Proceeding from or exhibiting great hostility or animosity.
4. Very difficult to accept or bear.

To a bitter degree

1. The taste experience when quinine or coffee is taken into the mouth; SYN. bitterness.
2. (British) Dry sharp-tasting ale with strong flavor of hops.

To make bitter.