acid indigestion

:  a sour substance

:  any of various typically water-soluble and sour compounds that in solution are capable of reacting with a base (see ¹base 7a) to form a salt, redden litmus, and have a pH less than 7, that are hydrogen-containing molecules or ions able to give up a proton to a base, or that are substances able to accept an unshared pair of electrons from a base

:  something incisive, biting, or sarcastic

:  sour, sharp, or biting to the taste

:  sharp, biting, or sour in manner, disposition, or nature

:  sharply clear, discerning, or pointed

:  inability to digest or difficulty in digesting something

:  a case or attack of indigestion marked especially by a burning sensation or discomfort in the upper abdomen