1) Embitter 2) Envenom 3) Irritate 4) Make bitter 5) Make sour or bitter 6) To exasperate 7) To irritate 8) To make bitter or sour 
to embitter; to irritate
• (v. t.) To sour; to imbitter; to irritate.
A·cerb'ate transitive verb [ Latin acerbatus , past participle of acerbare , from acerbus .] To sour; to imbitter; to irritate. 
[v] - make sour or bitter
acerbate To irritate or annoy.
verb make sour or bitter