acerbate

from WordNet (r) 3.0 (2006)

acerbate
    v 1: cause to be bitter or resentful; "These injustices
         embittered her even more" [syn: {embitter}, {envenom},
         {acerbate}]
    2: make sour or bitter

from The Collaborative International Dictionary of English v.0.48

Acerbate \A*cerb"ate\, v. t. [L. acerbatus, p. p. of acerbare,
   fr. acerbus.]
   To sour; to imbitter; to irritate.
   [1913 Webster]

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