The text’s editor links the term to Godefroy’s ostilier (tentatively glossed as ‘armourer’ and included in the DMF as outillier ‘Celui qui fabrique des outils’ ) but seems to interpret it as a variant of osteler¹, when he glosses the word as ‘host (=surety)’ (Gaunt² ii 420). Not only would outlier be an improbable form of these words, but historical evidence contradicts this interpretation, as Thomas the Bastard and William del Peek appeared together with Thomas le Molyneux before the barons of the Exchequer of Lancaster as outlaws of justice to receive a fine; see James L. Gillespie, ‘Thomas Mortimer and Thomas Molineux: Radcot Bridge and the Appeal of 1397’, Albion 7 (1975), 161-73 (p. 167).

It is not satisfactory to interpret the word as a deviant form of utlage, and the word outlier is attested in English, meaning an individual whose behaviour places him outside a community; OED outlier n. However, this term is not attested before the seventeenth century. In Middle English, only the related term outligger n. is attested, but it is limited to a nautical sense and refers to a type of spar. The corresponding verb, outlie v.1 (133733), i.e. ‘to lie on the outside of’, is attested once in Old English and then seems to disappear again until the seventeenth century. Could this passage be evidence of this word in the late fourteenth century?