defer

1325–75; Middle English deferren, variant of differren to differ

1. Defer, delay, postpone imply keeping something from occurring until a future time. To defer is to decide to do something later on: to defer making a payment. To delay is sometimes equivalent to defer, but usually it is to act in a dilatory manner and thus lay something aside: to delay one's departure. To postpone a thing is to put it off to (usually) some particular time in the future, with the intention of beginning or resuming it then: to postpone an election. 3. procrastinate.

Defer “to put off, delay” comes from Middle English deferen, differren “to put off, delay, be different, differentiate, refer a matter for decision; defer to, show respect or deference to,” from Old French def(f)erer, dif(f)erer “to have different qualities, be different, be dissimilar,” from Latin differre “to carry away, carry in different directions, differ, postpone, adjourn.” Differre is composed of the prefix dif- (a variant of dis- used before f ) “apart, asunder” and the simple verb ferre “to carry, bear.”
Defer and differ were originally the same word, but spellings with def- for etymologically correct dif-, which first appeared in the 15th century, have become standard in part because of the sense “to put off, delay” (absent in differ ), in part because of the accent being on the root (second) syllable, and in part through association with delay .
The meaning “to exempt temporarily from military service” first appeared in 1941.

1400–50; late Middle English deferren < Latin dēferre to carry from or down, report, accuse, equivalent to dē- de- + ferre to bear¹

Defer comes from Old French def(f)erer “to yield to, comply with,” from Latin dēferre “to carry, carry down, convey, report, inform, inform against, denounce.” Dēferre is a compound of the prefix and preposition dē-, dē, indicating privation, removal, and separation, and the simple verb ferre “to carry, bear” ( dēferre has no sense “to yield respectfully”). The sense “to yield respectfully, pay deference to,” which developed from the earlier sense “to submit for decision,” dates from the second half of the 17th century.