noun
one arrow; a single arrow
Literal meaning; often used in historical or archery contexts. In modern Japanese, it is most commonly encountered in the fixed expression 一矢を報いる.
彼は一矢を放ったが、的に当たらなかった。
He shot a single arrow, but it missed the target.
noun
retort; a comeback; a counterattack
Idiomatic use, almost exclusively in the phrase 一矢を報いる (to retaliate, to get a jab in, to return fire). The word 一矢 itself is not freely used to mean 'retort' outside this expression.
See also: 一矢を報いる
彼は批判に対して一矢を報いた。
He retorted against the criticism.
チームは終盤に一矢を報いるゴールを決めた。
The team scored a goal late in the game to get one back.