/ klɪntʃ; NAmE / verb , noun
■ verb [ vn ]
1.
to succeed in achieving or winning sth :
to clinch an argument / a deal / a victory
2.
to provide the answer to sth; to settle sth that was not certain :
'I'll pay your airfare.' 'Okay, that clinches it —I'll come with you.'
a clinching argument
■ noun
1.
( informal ) a position in which two lovers hold each other tightly
SYN embrace
2.
a position in a fight in which two opponents hold each other tightly
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WORD ORIGIN
late 16th cent. (in the senses something that grips and fix securely ): variant of clench .