1. (verb)unblock clear or remove an obstruction from
"the procedure unblocked his arteries"
2. (verb)unblock play the cards of (a suit) so that the last trick on which a hand can follow suit will be taken by a higher card in the hand of a partner who has the remaining cards of a combined holding
3. (verb)unblock, unfreeze, free, release make (assets) available
"release the holdings in the dictator's bank account"