champ (n.) Look up champ at
1868, American English abbreviation of champion (n.).
champ (v.) Look up champ at
"to chew noisily," 1520s, probably echoic; OED suggests a connection with jam (v.). Earlier also cham, chamb, etc. (late 14c.). To champ on (or at) the bit, as an eager horse will, is attested in figurative sense by 1640s. Related: Champed; champing. As a noun in this sense, attested from c. 1600.