Akkadian

nakkaptu - temple (CAD N₁ 184, AHw. 722)

Double ­-kk­- remains to be explained. One of possible interpretations is nakkaptu < *ma-nkap-t- (on na- < *ma- see [GAG 39], on -­kk- < *-­nk- see [ibid. 42]).

PS
*nakap-at- - temple, cheek-bone (SED I No. 199; Kogan 2011: 220)

Scarcely but reliably attested in Akk. and Arb. only.