noun
A person who is excessively sentimental or who values sentiment over reason. Often used with a slightly critical or ironic tone.
彼は筋金入りのセンチメンタリストで、古い映画を見るたびに泣いてしまう。
He is a dyed-in-the-wool sentimentalist who cries every time he watches an old movie.
Adjectival form meaning 'sentimental'; センチメンタリスト refers specifically to a person with that trait.
Borrowed from English 'sentimentalist'.