'Sentiment' is Latin for 'a feeling' — once neutral, it soured after Sterne made 'sentimental' trendy.
A view or opinion that is held or expressed; a feeling or emotion; exaggerated or self-indulgent feelings of tenderness, sadness, or nostalgia.
From Old French 'sentement' (feeling, opinion, perception), from Medieval Latin 'sentīmentum,' from Latin 'sentīre' (to feel, to perceive, to sense, to think), from a Proto-Italic form *sent- whose deeper PIE etymology is debated — some scholars connect it to PIE *sent- (to go, to head for, to take a path), suggesting that feeling was originally conceived as 'heading toward' or 'finding one's way' through sensory experience. Latin 'sentīre' is one of the great sensory verbs of the Western tradition, producing 'sense,' 'sensation,' 'sentence' (originally a feeling or opinion, then a judicial opinion, then a grammatical unit expressing one), 'sentient,' 'consent' (to feel together), 'dissent' (to feel apart), 'resent' (to feel again, i.e., to feel an injury
The word 'sentimental' was popularized by Laurence Sterne's novel 'A Sentimental Journey Through France and Italy' (1768), where it meant 'guided by refined feeling.' Within a generation, the word had already begun to sour, acquiring its modern negative connotation of excessively emotional or mawkish. Sterne intended a compliment; posterity turned it into a criticism.