The Collaborative International Dictionary of English v.0.48:
Chockablock \Chock"a*block\, a. (Naut.) Hoisted as high as the tackle will admit; brought close together, as the two blocks of a tackle in hoisting. [1913 Webster] Chock-fullWordNet (r) 3.0 (2006):
chock-a-block adv 1: as completely as possible; "it was chock-a-block full" [syn: chock, chock-a-block]