empty (adj.) Look up empty at Dictionary.com
c. 1200, from Old English æmettig "at leisure, not occupied; unmarried," also "containing nothing, unoccupied," from æmetta "leisure," from æ "not" + -metta, from motan "to have" (see might (n.)). The -p- is a euphonic insertion.

Sense evolution from "at leisure" to "containing nothing, unoccupied" is paralleled in several languages, such as Modern Greek adeios "empty," originally "freedom from fear," from deios "fear." "The adj. adeios must have been applied first to persons who enjoyed freedom from duties, leisure, and so were unoccupied, whence it was extended to objects that were unoccupied" [Buck]. Related: Emptier. Figurative sense of empty-nester attested by 1960.
empty (n.) Look up empty at Dictionary.com
"an empty thing" that was or is expected to be full, 1865, from empty (adj.). At first of barges, freight cars, mail pouches.
empty (v.) Look up empty at Dictionary.com
1520s, from empty (adj.); replacing Middle English empten, from Old English geæmtigian. Related: Emptied; emptying.