talk trash

Etymology
Phrasal verb from +.

Verb

 * 1)  To untruthfully speak of another in a belittling, deprecative, slighting manner, either in person or in absentia.
 * 2)  To speak boastfully or tauntingly about oneself in contrast with another person or other people.
 * 1)  To speak boastfully or tauntingly about oneself in contrast with another person or other people.

Usage notes

 * This is an idiomatic instance of a general construction consisting of talk with the topic area as object of the verb. One can talk baseball, talk philosophy, or talk shop.

Synonyms

 * (slang, vulgar)