A person who helps with a task; often used for someone lending a hand in work or daily chores.
引っ越しの手伝い手を探している。
I'm looking for someone to help with the move.
彼はいつも料理の手伝い手になってくれる。
He always helps out with the cooking.
Compound of 手伝い (help, assistance) and 手 (person, -er), literally 'helping hand person'.