Answer: acerbate

AnswerCrossword Clue
ACERBATEMake bitter
ACERBATEMake sour
ACERBATEEmbitter
ACERBATEVex
ACERBATEIrritate
acerbateto exasperate
acerbateto embitter (to make bitter, also IMBITTER)
acerbateto make sour or bitter
acerbatefeeling or expressing bitterness or annoyance