The adjective luke sems to be an alternative form of lew, Old English hleow, which meant 'tepid" in the 14th century. AnswerParty!
Old English (Ænglisc, Anglisc, Englisc) or Anglo-Saxon is an early form of the English language that was spoken and written by the Anglo-Saxons and their descendants in parts of what are now England and southern and eastern Scotland between at least the mid-5th century and the mid-12th century. What survives through writing represents primarily the literary register of Anglo-Saxon.
It is a West Germanic language closely related to Old Frisian and Old Saxon. Old English had a grammar similar in many ways to Classical Latin. In most respects, including its grammar, it was much closer to modern German and Icelandic than to modern English. It was fully inflected with five grammatical cases (nominative, accusative, genitive, dative, and instrumental), three grammatical numbers (singular, plural, and dual) and three grammatical genders (masculine, feminine, and neuter). The dual forms occurred in the first and second persons only and referred to groups of two.