Brown Driver Briggs

 1. to pledge, exchange, mortgage, engage, occupy, undertake for, give
pledges, be or become surety, take on pledge, give in pledge
  1) (Qal)
1a1. to take on pledge, go surety for
1a2. to give in pledge
1a3. to exchange
1a4. to pledge
  2) (Hithpael)
1b1. to exchange pledges
1b2. to have fellowship with, share