WA merke, mirk, mirke
'dark, obscure, darkness'(Modern English murk)
The absence of palatalization in ME merk has led some commentators to cautiously suggest it could derive from ON, cp. OIcel myrkr 'dark, murky', rather than its OE cognate mirce 'murky, dark, black, uncanny, evil' (see e.g. Bj., McGee 405, Anderson and, for the adj. only, GollCl). These derive from < PGmc *merkwa- (cp. also OS mirki 'eery, evil'), where the original /w/ following the velar stop might have prevented this change in OE, however, so this is not a clear test of loan (as OED3 notes, and see Luick §637 note 4).
Proposed ON Etymon (OIcel representative)
myrkr 'dark, murky', cp. myrkr 'darkness'
(ONP myrkr (adj.), cp. myrkr (sb.))
Other Scandinavian Reflexes
Far myrkur, Icel myrkur, Norw myrk, Dan mørk, Sw mörk
mirce (adj.) 'murky, dark, black, uncanny, evil', mirce (n.) 'murkiness, darkness'
Phonological and morphological markers
[absence of palatalization of */k/] (possibly diagnostic)
MED's first citation of the adj. occurs (in a figurative sense) in a1300(a1250) Bestiary (Arun 292), and it occurs frequently thereafter, particularly, but not exclusively, in N and E texts. The n. similarly occurs early in a1400(c1303) Mannyng HS (Hrl 1701) and ?a1400(a1338) Mannyng Chron.Pt.2 (Petyt 511) and PP, but MED's subsequent citations are all from N texts.
Occurrences in the Gersum Corpus
Cl 894, 1617; Pat 291; WA 374, 2042, 3851 etc.