The Collaborative International Dictionary of English v.0.48:
Pledger \Pledg"er\, n. One who pledges. [1913 Webster]WordNet (r) 3.0 (2006):
pledger n 1: someone who makes or gives a pledgeBouvier's Law Dictionary, Revised 6th Ed (1856):
PLEDGER. The same as pawner. (q.v.)