† ˈlastful,a.Obs.rare. Also 1 ᵹelástful. [f.OE.ᵹe-lást duty + -ful.] Helpful, serviceable. c1000Laws of æthelstan vi. c. 4 (Schmid) 160 Ðæt ælc man wære oðrum ᵹelastfull.c1200Trin. Coll.Hom. 183 Þu ware me lastful on alle þo þe ich wolde we ware onmode godes wille to done.