Mockery that's awfully crass about alpha male (7)
I believe the answer is:
sarcasm
'mockery' is the definition.
(I've seen this before)
'awfully crass about alpha male' is the wordplay.
'awfully' is an anagram indicator.
'about' indicates putting letters inside.
'alpha' becomes 'a' (phonetic alphabet: alpha, bravo, charlie etc.).
'male' becomes 'm' (common abbreviation).
'crass' anagrammed gives 'sarcs'.
'sarcs' enclosing 'a' is 'sarcas'.
'sarcas'+'m'='SARCASM'
'that's' is the link.
(Other definitions for sarcasm that I've seen before include "Caustic remarks" , "Ironically scornful language" , "Scornful jibe" , "Language expressing scorn or contempt" , "Ironic mockery" .)