defileyoudaoicibaDictYouDict
defile: Defile ‘make dirty’ [14] and defile ‘narrow pass’ [17] are distinct words in English. The former has a rather complex history. It was originally acquired in the 13th century as defoul, borrowed from Old French defouler ‘trample down, injure’; this was a compound verb formed from the prefix de- ‘down’ and fouler ‘tread’, which in turn goes back via Vulgar Latin *fullāre to Latin fullō ‘person who cleans and thickens cloth by stamping on it’, source of English fuller [OE].

In the 14th century defoul started to turn into defile under the influence of the synonymous (and now obsolete) befile [OE], a compound verb derived ultimately from the adjective foul. Defile ‘narrow pass’ was borrowed from French défilé, originally the past participle of défiler, a compound verb based on filer ‘march in a column’ (which is a close relative of English file).

=> fuller; file
defile (n.)youdaoicibaDictYouDict
"narrow passage," 1640s, especially in a military sense, "a narrow passage down which troops can march only in single file," from French défilé, noun use of past participle of défiler "march by files" (17c.), from de- "off" (see de-) + file "row," from Latin filum "thread" (see file (v.1)). The verb in this sense is 1705, from French défiler.
enfilade (n.)youdaoicibaDictYouDict
1706, a string of things in a straight line, from French enfilade, from Old French enfiler (13c.) "to thread (a needle) on a string; pierce from end to end," from en- "put on" (see en- (1)) + fil "thread" (see file (v.1)). Used of rows of apartments and lines of trees before military sense came to predominate: "a firing with a straight passage down ranks of men, channels in fortifications, etc." (1796). As a verb from 1706 in the military sense, "rake with shot through the full length." Related: Enfiladed; enfilading. The Old French verb was borrowed in Middle English as enfile "to put (something) on a thread or string."
file (v.1)youdaoicibaDictYouDict
"place (papers) in consecutive order for future reference," mid-15c., from Old French filer "string documents on a thread or wire for preservation or reference" (15c.), earlier "to spin thread," from fil "thread, string" (12c.), from Latin filum "a thread, string; thread of fate; cord, filament," from PIE *gwhis-lom (cognates: Armenian jil "sinew, string, line," Lithuanian gysla "vein, sinew," Old Church Slavonic zila "vein"), from root *gwhi- "thread, tendon." The notion is of documents hung up on a line in consecutive order for ease of reference.
File (filacium) is a threed or wyer, whereon writs, or other exhibits in courts, are fastened for the better keeping of them. [Cowel, "The Interpreter," 1607]
Methods have become more sophisticated, but the word has stuck. Meaning "place among the records of a court or office" is from 1510s; of newspaper reporters sending in stories, 1954. Intransitive sense "march in a line (as soldiers do) one after another" is from 1610s. Related: Filed; filing.
file (n.1)youdaoicibaDictYouDict
1520s, "string or wire on which documents are strung," from French file "a row" (15c.), noun derived from Middle French filer "string documents; spin thread" (see file (v.1)). The literal sense explains why from the beginning until recently things were generally on file (or upon file). The meaning "collection of papers systematically arranged for ready reference" is from 1620s; computer sense is from 1954. The sense "row of persons or things one behind another" (1590s) is originally military, from the French verb in the sense of "march in file." Meaning "line of squares on a chessboard running directly from player to player" is from 1610s.
French (adj.)youdaoicibaDictYouDict
c. 1200, frensh, frenche, "pertaining to France or the French," from Old English frencisc "French," originally "of the Franks," from franca, the people name (see Frank). A similar contraction of -ish is in Dutch, Scotch, Welsh, suggesting the habit applies to the names of only the intimate neighbors.

In some provincial forms of English it could mean simply "foreign." Used in many combination-words, often dealing with food or sex: French dressing (by 1860); French toast (1630s); French letter "condom" (c. 1856, perhaps on resemblance of sheepskin and parchment), french (v.) "perform oral sex on," and French kiss (1923) all probably stem from the Anglo-Saxon equation of Gallic culture and sexual sophistication, a sense first recorded 1749 in the phrase French novel. (In late 19c.-early 20c., a French kiss was a kiss on each cheek.) French-Canadian is from 1774; french doors is by 1847. To take French leave, "depart without telling the host," is 1771, from a social custom then prevalent. However, this is said to be called in France filer à l'anglaise, literally "to take English leave."
French leaveyoudaoicibaDictYouDict
"Absence from work or duty without permission", Mid 18th century: said to derive from the French custom of leaving a dinner or ball without saying goodbye to the host or hostess. The phrase was first recorded shortly after the Seven Years War; the equivalent French expression is filer à l'Anglaise, literally 'to escape in the style of the English'.