Etymology: < mis- prefix¹ + Middle English trowe, variant of truce n., after mistrow v. Compare Norwegian mistru, Old Swedish mistro (Swedish misstro), Danish mistro.The β. forms (all attested in manuscripts of the northern Middle English text Cursor Mundi) are probably partly after early Scandinavian forms with suffixed definite article in -n, and partly after forms of mistrow v. with final -n (see discussion at that entry).

Etymology: < mis- prefix¹ + trow v., probably influenced by early Scandinavian (compare Old Icelandic mistrúa , Old Swedish mistroa , mistro (Swedish misstro ), Danish mistro , all < the Scandinavian base of Old Icelandic mis- mis- prefix¹ + the Scandinavian base of Old Icelandic trúa trow v.). In recent Shetland use probably < the unattested Norn reflex of the early Scandinavian word represented by the Scandinavian forms listed above.Middle English forms of this word with retention of the final -n of the infinitive occur several times in the text of Cursor Mundi (in this text the infinitive ending -n has generally been lost); such forms were probably originally retained for the purposes of the rhyme (compare quot. a1400² at sense 1), but a genuine variant in -n does seem to have arisen by apprehension of the ending -n as part of the stem (compare the form mistrowne in quot. a1400² at sense 3, not in a rhyming position, and the form mistrouning in quot. a1400 at mistrowing n.¹; compare also forms in -n s.v. mistrow n.). Recorded in Sc. National Dict. s.v. Mistrue, in sense 1 from Shetland in 1963.