(di·fīl′) v.t. ·filed, ·fil·ing
1. To make foul or dirty; pollute.
2. To tarnish or sully the brightness of; corrupt the purity of.
3. To sully; profane (a name, reputation, etc.).
4. To render ceremonially unclean.
5. To corrupt the chastity of. [<OF defouler <de- down (<L de-) + fouler trample; infl. in form by ME filen soil, OE fӯlan <fūl foul]
—de·file′ment noun
—de·fil′er noun Synonyms: befoul, contaminate, corrupt, infect, pollute, soil, spoil, stain, sully, taint, tarnish, vitiate. The hand may be defiled by a touch of pitch; swine that have been wallowing in the mud are befouled. Contaminate and infect refer to something evil that deeply pervades and permeates, as the human body or mind. Pollute is used chiefly of liquids; as, water polluted with sewage. Tainted meat is repulsive; infected meat contains germs of disease. A soiled garment may be cleansed by washing; a spoiled garment is beyond cleansing or repair. Bright metal is tarnished by exposure; a fair sheet is sullied by a dirty hand. We speak of a vitiated taste or style; fraud vitiates a title or a contract. See ABUSE, CORRUPT, POLLUTE, VIOLATE. Antonyms: clean, cleanse, disinfect, hallow, purify, sanctify.

(di·fīl′, dē′fīl) v.i. ·filed, ·fil·ing
To march in a line or by files; file off.
—noun
1. A long narrow pass; a gorge between mountains.
2. A marching in file. [<MF défiler <dé- down (<L de-) + file FILE¹ (def. 3)]