[wú xiào]
of no avail; to no avail; invalid; null and void; nullity (合同等的); in vain; unavailability; ineffectiveness; inefficiency; futility; flop
nullify an election
宣布选举无效
fail to respond to medical treatment
医治无效
declare decision invalid
宣布决定无效
an invalid contract
无效的契约
make the investment inefficient
无效投资