smartass

Short definition from Wiktionary

Noun

1. 1
   Synonym of know-it-all, an obnoxious clever person or a person making obnoxious efforts to seem clever by acting or behaving as if they know everything.
2. 2
   An insolent person, especially one who makes snide remarks.

Adjective

1. 1
   Related to or characteristic of a smartass; irritatingly clever or smug.

Verb

1. 1
   To talk like a smartass, with a lot of snide remarks.