1962, American English, from common pronunciation of SNCC, initialism (acronym) for "Student Non-violent Co-ordinating Committee," black civil rights organization.
snick (v.)
"cut, clip, snip," c. 1700, back-formation from snickersnee.
sneaky
sneer
sneeze
sneezy
snell
snick
snicker
snickersnee
snide
sniff
sniffer