Etymology

Always derived from ON, cp. OIcel agi ‘dread, awe; discipline; enmity’, a masc. n-stem formation on PGmc *ag-.  This stem-formative is only known in Scandinavia, in contrast with the declensional types attested in OE, viz. OE ege ‘fear, awe’ (a str. masc. n. apparently originating in an es-stem *agiz, cp. Go agis), and egesa (a wk. masc. representing an n-stem extension of the same, i.e. *agisan; cp. OS egiso, OHG agiso, egiso). An OE n-stem on the same root is nonetheless conceivable, and would have given *aga without i-mutation or palatalization. See also aghlich and aʒlez.

PGmc Ancestor

*ag-

Proposed ON Etymon (OIcel representative)

agi ‘dread, awe; discipline; enmity’
(ONP agi (sb.))

Other Scandinavian Reflexes

Far agi, Icel agi, Norw age, Dan ave, OSw aghi, Sw aga

OE Cognate

cp. ege (n.) ‘fear, awe’

Phonological and morphological markers

Summary category

C1c

Attestation

N and E in earlier ME (first recorded in Orrm), but shows signs of wider acceptance by the later period (incl. Chaucer, in rhyme): see further McGee 507. 

Occurrences in the Gersum Corpus

Erk 234, WA 169, 1459, 2987 etc.

Bibliography

MED aue (n.) , OED awe (n.1) , HTOED , Bj. 30n.1, 199, 305-6, de Vries agi, Mag. agi (1), Bj-L age, Orel *aʒez, Kroonen *agiz-, AEW ege