WA superl. tethiest, theþeest, tithiest, tidiest
'excellent' (Modern English )
Proposed ON Etymon (OIcel representative)
tíðr 'frequent, usual, customary, noted, famous, beloved, eager'
(ONP tíðr (2) (adj.))
Other Scandinavian Reflexes
Far tíður, Icel tíður, Norw tid, Dan tith
cp. tīd (n.) ‘time’
Phonological and morphological markers
[ON fricative /ð/ < PGmc */ð/] (may not be applicable)
MED cites relevant senses from a handful of texts beginning with a1375 WPal. (KC 13) and including DT, PP and Lydgate. The variant spellings attested in WA, however, lead the OED to create an entry for an adj. tethy, which it cites only from this text.
Occurrences in the Gersum Corpus
WA 663, 2198, 2371, etc.
Skeat WA read teche at 663, but all others read tehte, which gives a much better sense (see TPD 663n)