Definition of bittered:
(adj) :
Having an acrid taste (usually from a basic substance).
(adj) :
Harsh, piercing, acerbic or stinging.
(adj) :
Hateful or hostile.
(adj) :
Cynical and resentful.
(adv) :
To an intense or severe degree; bitterly.
(n) :
(usually in the plural bitters) A liquid or powder, made from bitter herbs, used in mixed drinks or as a tonic.