romantic lead (acting); philanderer
Uncommon word. In acting contexts, refers to a performer specializing in romantic roles. More broadly, can label a man known for many love affairs.
He was known as a romantic lead in kabuki.
That actor only plays romantic lead roles.
Compound of 濡れ事 (love affair, from 濡れる 'to get wet' metaphorically extended to romantic involvement) and 師 (master, specialist). The exact historical derivation is uncertain.