Bitterness is a related term of maliciousness.
As nouns the difference between bitterness and maliciousness
is that bitterness is the quality of having a bitter taste while maliciousness is the condition of being malicious; malevolence or malice.
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
maliciousness
English
Noun
The condition of being malicious; malevolence or malice