decider; person who decides
Less common than the factor sense; used for a person or party whose judgment or action settles the matter, especially where someone has the deciding role.
If the votes are tied, the committee chair becomes the decider.
decisive factor; clincher; key; trump card; conclusive evidence
The common modern use: the factor, evidence, move, or blow that settles a choice, argument, contest, or outcome. Often appears as 決め手になる, 決め手を欠く, or 決め手がない.
The low price was the deciding factor in the purchase.
There is still no conclusive evidence identifying the culprit.
The three-point shot near the end became the decisive play of the game.
His testimony became the decisive factor in solving the case.
There's still no decisive factor for choosing between the two proposals.
The investigation team was desperate to find the decisive piece of evidence in the case.
This photograph became the key piece of evidence for identifying the culprit.
証拠 specifically means evidence or proof, whereas 決め手 more broadly covers any factor, move, or piece of evidence that settles a matter.
要因 is a neutral term for a contributing factor or cause, while 決め手 specifically singles out the factor that clinches or decides the outcome.
決め手 is a general term for the decisive factor or finishing move in any contest or argument, while 決め球 specifically refers to a pitcher's go-to pitch in baseball.
Standard and common spelling; lists high-priority news and frequency tags for this form.
Rare kanji spelling marked as rarely used; use 決め手 in normal writing.
A compound of 決め, the continuative noun-like form of 決める, and 手, which can mean a person involved in an action or a means/move. The spelling 決め手 is conventionally tied to deciding or settling something.