to make foul, dirty, or unclean; pollute; taint; debase.
2.
to violate the chastity of.
3.
to make impure for ceremonial use; desecrate.
4.
to sully, as a person's reputation.
Origin: 1275–1325; ME defilen, defelen, alter. of defoilen (by assoc. with filen to file3) < AF, OF defouler to trample on, violate; cf. OE befȳlan to befoul
"make filthy," c.1280, from O.Fr. defouler "trample down, violate," from de- "down" + fouler "to tread," from L. fullo "person who cleans and thickens cloth by stamping on it." Sense infl. by foul (q.v.); spelling infl. by obsolete native befile, which it replaced and which meant about the same thing.
[di-fahyl] 
