Origin and history of compliance

early 14c., complien, "to carry out, fulfill" (transitive), probably from Old French compli, past participle of complir "to accomplish, fulfill, carry out," from Vulgar Latin *complire, from Latin complere "to fill up," transferred to "fulfill, finish (a task)," from com-, here probably as an intensive prefix (see com-), + plere "to fill" (from PIE root *pele- (1) "to fill").

The intransitive sense of "to consent, act in accordance with another's will or desire" is attested from c. 1600 and might have been influenced by ply (v.2), or perhaps it is a reintroduction from Italian, where complire had come to mean "satisfy by 'filling up' the forms of courtesy" (compare compliment (n.)).

also noncompliance, "failure or refusal to comply," 1680s, from non- + compliance. Related: Noncompliant.

word-forming element attached to verbs to form abstract nouns of process or fact (convergence from converge), or of state or quality (absence from absent); ultimately from Latin -antia and -entia, which depended on the vowel in the stem word, from PIE *-nt-, adjectival suffix.

Latin present-participle endings for verbs stems in -a- were distinguished from those in -i- and -e-. Hence Modern English protestant, opponent, obedient from Latin protestare, opponere, obedire.

As Old French evolved from Latin, these were leveled to -ance, but later French borrowings from Latin (some of them subsequently passed to English) used the appropriate Latin form of the ending, as did words borrowed by English directly from Latin (diligence, absence).

English thus inherited a confused mass of words from French (crescent/croissant), and further confused it since c. 1500 by restoring -ence selectively in some forms of these words to conform with Latin. Thus dependant, but independence, etc.