noun
Formal term used in official, political, or organizational contexts to indicate refusal to approve, rejection of a proposal, or exercise of veto power.
理事会はその提案を不承認とした。
The board disapproved the proposal.
大統領は法案に不承認の意
The president indicated dissent against the bill.
否決 means voting down or rejecting a motion, emphasizing the voting process; 不承認 focuses on the act of not granting approval, which may or may not involve a vote.
Compound of 不 (fu, 'not') and 承認 (shōnin, 'approval, recognition'). The word follows standard Sino-Japanese word formation patterns.