to employ a person (as); to take part in an activity

hire for job, use

(money paid for) the act of hiring; to obtain the use of (something) in return for payment

commission for responsibility, use

to (agree to) pay (a sum of money) regularly (to a cause, for something)

pay for use; contribute

a person who offers to do something (especially unpleasant or dangerous, or without being paid); to report (something) without being asked

offer to do something