Refers to a short-bladed weapon, often a double-edged dagger. The reading あいくち is standard; ひしゅ is a rare alternative reading.
See also: 合口 (あいくち)
He carried a dagger for self-defense.
In period dramas, assassination scenes using a dagger often appear.
Standard kanji form for the reading あいくち. The reading ひしゅ is rare and not typically used with this kanji.
Kana spelling is common in everyday writing, especially when the kanji is obscure.
The kanji 匕首 are ateji (characters used for their sounds) for the native Japanese word あいくち. The reading ひしゅ is a Sino-Japanese reading of the same characters, but it is rarely used.