empty (adj.)youdaoicibaDictYouDict
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.