† aˈssubtile,v.Obs.rare—1. [a. OF.assubtiller, -ier, refash. form of assoutiller, -ier, cogn. with It.assottigliare, f. Latin type *adsubtīliāre, f.ad- to + subtīlis subtle.] To subtilize. 1589Puttenham Eng. Poesie i. iii. (Arb.) 23 Much abstinence..assubtiling and refining their spirits.