gall 1 
(gôl)
(gôl)n.
1. Outrageous insolence; effrontery: After borrowing my car, he had the gall to complain about its seats.
2.
a. Bitterness of feeling; rancor.
b. Something bitter to endure: the gall of defeat.
3. See bile.
[Middle English galle, gallbladder, bile, courage, from Old English gealla, galla, bile; see ghel-2 in the Appendix of Indo-European roots.]