noun
substitute for a proper greeting; something given in lieu of a greeting
Refers to a gift, gesture, or action that serves as an informal greeting, often when a proper verbal greeting is omitted or replaced.
手土産を挨拶代わりに渡した。
I gave a small gift as a substitute for a proper greeting.
軽く会釈するのが挨拶代わりだった。
A slight bow served as a greeting.
Compound of 挨拶 (aisatsu, 'greeting') + 代わり (kawari, 'substitute').