Etymology

OE *drepan (whose present tense is not attested) meant only ‘to strike’ (literal or figurative), next to the extended range of senses associated with its ON cognate, cp. OIcel drepa ‘to strike a (violent) blow, knock down, deliver (a fatal) blow; kill, destroy, slaughter (etc.)’ (and cp. further OS ofer-drepan ‘to outdo, surpass’, OHG treffan ‘to strike’) and thus arguements have been made for ON semantic influence on the v. when (in ChronE 1137 and predominantly N and E ME) it means ‘to kill’ (thus Kluge 1901: 933, TGD, Olszewska 1937: 61–2, McGee 326–7, 476–7). But the sense development from ‘strike’ to ‘kill’ is straightforward and a native etymon is assumed by most commentators (so OED, MED, GDS).

PGmc Ancestor

*drepan-

Proposed ON Etymon (OIcel representative)

drepa ‘to strike a (violent) blow, knock down, deliver (a fatal) blow; kill, destroy, slaughter (etc.)’ 
(ONP drepa (vb.))

Other Scandinavian Reflexes

Far droypa, Icel drepa, Norw drøypa, Sw dröpa

OE Cognate

drepan 'to strike'

Phonological and morphological markers

Summary category

CCC3c

Attestation

The earliest witness to the ‘kill’ sense is ChronE 1137 (see DOE). MED (which does not distinguish between the ‘kill’ and ‘strike’ meanings) cites a handful of occurrences, the great majority in N and E texts.

Occurrences in the Gersum Corpus

Gaw 725; Cl 246, 599, 1306 etc.; WA 744, 867, 961 etc.

Bibliography

MED drēpen (v.1) , OED drepe (v.) , HTOED , Dance dreped, Bj. 86, 234–5, de Vries drepa, Mag. drepa, Bj-L. drepe, Seebold drep-a-, Orel *ðrepanan, Kroonen *drepan-, AEW drepan, DOE drepan