Describes a person who speaks smoothly and persuasively, often with a nuance of being a smooth talker. Can be used positively or with slight suspicion.
He is smooth-spoken and quickly gets along with anyone.
Be careful of glib salespeople.
Compound of 口 (mouth, speech) and 巧者 (skillful person). The exact historical derivation is uncertain, but the word literally suggests a person skilled with words.