反酸

acid reflux / regurgitation

contrary / in reverse / inside out or upside down / to reverse / to return / to oppose / opposite / against / anti- / to rebel / to use analogy / instead / abbr. for 反切[fan3 qie4] phonetic system

sour / tart / sick at heart / grieved / sore / aching / pedantic / impractical / to make sarcastic remarks about sb / an acid