[im'bitә]
vt.
加苦味于, 使受苦, 使难受, 使怨恨, 加重

Imbitter \Im*bit"ter\, v. t. [imp. & p. p. {Imbittered}; p. pr.
& vb. n. {Imbittering}.] [Pref. im- in + bitter. Cf.
{Embitter}.] [Written also {embitter}.]
To make bitter; hence, to make distressing or more
distressing; to make sad, morose, sour, or malignant.

Is there anything that more imbitters the enjoyment of
this life than shame? --South.

Imbittered against each other by former contests.
--Bancroft.