Refers to a person who commits murder, especially a hired or political killer. A somewhat formal or literary term.
The politician was attacked by an assassin.
The murderer in the case has not been caught yet.
殺人犯 is the standard legal term for 'murderer', whereas 凶手 carries a more dramatic or old-fashioned nuance.
Standard kanji spelling.
Variant using the older 兇 character; less common in modern usage.
凶 (bad, evil) + 手 (hand, person). The exact historical derivation is uncertain, but the compound suggests 'evil hand' or 'person who commits a violent act'.