As nouns the difference between bitterness and trenchancy
is that bitterness is the quality of having a bitter taste while trenchancy is the quality of being trenchant.
bitterness
English
Noun
the quality of having a bitter taste
the quality of feeling bitter; acrimony, resentment
Synonyms
* (quality of being bitter in taste) acerbicness, acridity, acridness
* (quality of feeling bitter) acrimony, gall, rancor/rancour, resentment
trenchancy
English
Noun
(trenchancies)
the quality of being trenchant
irony or bitterness of tone