sucker
n. countablen. a person who is easily tricked or fooled because they are too trusting. You can also use it to describe someone who likes a specific thing very much.
n. a person who is easily deceived or manipulated; a dupe. In a more positive informal sense, it refers to someone with a strong, often irrational, attraction to a specific thing.
He is such a sucker for a good sales pitch.
The scammers targeted him because they knew he was a sucker for any 'get rich quick' scheme.
While he considered himself a hardened cynic, he remained a total sucker for classic Hollywood romances, often finding himself moved to tears by the predictable happy endings.
From Middle English souker, sokere, sukkere, soukere, equivalent to suck (verb) + -er. Compare Saterland Frisian Suuger, West Frisian sûker (“sucker”), Dutch zuiger (“sucker”), German Sauger (“dummy; vacuum”).
Possibly from German Sache (“thing”).
Informal in register. Often used in the construction 'a sucker for [something]' to indicate a strong liking.