Wordnet 3.0
NOUN (1)
1. 
 an impudent or insolent rejoinder; 
- Example: "don't give me any of your sass"[syn: sass, sassing, backtalk, back talk, lip, mouth]
VERB (1)
1.  answer back in an impudent or insolent manner; 
- Example: "don't sass me!"
- Example: "The teacher punished the students who were sassing all morning";
WordNet (r) 3.0 (2006):
sass
    n 1: an impudent or insolent rejoinder; "don't give me any of
         your sass" [syn: sass, sassing, backtalk, back
         talk, lip, mouth]
    v 1: answer back in an impudent or insolent manner; "don't sass
         me!"; "The teacher punished the students who were sassing
         all morning";