'harassed, driven'(Modern English teise)
There is no etymology for this word that fully accounts for both its form and sense, and the case for ON derivation is as plausible as any: (1) Most authorities compare it to two formally similar but semantically distant words: (a) OE (ge)tǣsan ‘to pull, tear, comb, card; wound, injure, assault; influence’; cp. Sw dial tēsa ‘to pluck, to pull to pieces’, Dan dial tǣse, tēse ‘to tease (wool)’, WFris tiezje ‘to confuse’, MLG tēsen ‘to twitch, to scratch’, OHG zeisin ‘to card (wool)’, supposing a PGmc wk. 1 v. *taisjan- formed on the a-grade of the str. vb. *taisan- as in OHG zeisan ‘to pluck, gather’. While the OE v. accounts very well for forms of ME tesen in /ɛ:/ and PDE tease, it does not accord with ME /ai,ei/. (b) Vocalically, a better fit is OFr teser (pres. 3 sg. teise, toise), AN teser (teiser) ‘to stretch, bend (a bow), < a late Lat. *tēsāre < tensāre formed on Lat. tensus ‘stretched, bent’ (the source of ME teisen ‘to aim an arrow’ (etc.), attested from the late 14c). The sense, however, is distant from ME taysed and OED argues that it was only in its late use that ME taysed came to be associated with PDE tease; the two originally distinct words (i.e. OE tǣsan and OFr teser) evidently did become confused to some extent (cp. in MED). Neither, however, accounts transparently for the meaning 'harassed, driven', although the OE can denote violent activity beyond that applied to wool (see esp. Mald 270, B-T and CH s.vv.). Thus it is possible to posit a generalisation of the sense to denote physical treatment more broadly, in line with EDD's sense 3 of tease 'to handle roughly; to tear; to toss about; also used fig.' One could also posit a metaphorical extension in ME of the idea of 'teasing' roughly analogous to the later meanings of tease, i.e. 'worry or irritate by persistent action which vexes or annoys' (recorded in OED from the 17c.), in this case 'harass (physically)' > 'chase'. (2) Alternatively, derivation from an ON *teisa (represented by the Dan and Sw dial words cited in (1) and cognate with OE tǣsan) would provide a good match to the ME phonologically, although the same problems of sense development remain as with the OE cognate, i.e. an original sense 'pluck, pull (esp. of wool etc.)' to 'harass, drive'.
(1a) *taisjan-; (2) *taisjan-
Proposed ON Etymon (OIcel representative)
Other Scandinavian Reflexes
(2) Dan dial tǣse, tēse, Sw dial tēsa
(1a) (ge)tǣsan ‘to pull, tear, comb, card; wound, injure, assault; influence’
Phonological and morphological markers
MED's only other citation for its for sense (e) (‘hunt. to drive (an animal) by harassing, chase’) is from (c1410) York MGame (Vsp B.12), which is also spelt with a digraph (<teise>); comparable spellings listed under other senses are c1500 Recipe MSS Hast.in HMC (Hnt HU 1051) 1.423 <teise> and a1425(a1399) Form Cury (Add 5016) 102.22/10 <yteysed>.
Occurrences in the Gersum Corpus
On the sense at Gaw 1169, see Wright 1906: 223.