subtilise

WordReference Random House Unabridged Dictionary of American English © 2025

sub•til•ize  (sut′l īz′, sub′tə līz′), v., -ized, -iz•ing. 
v.t. 

1. to elevate in character;
   sublimate.
2. to make (the mind, senses, etc.) keen or discerning;
   sharpen.
3. to introduce subtleties into or argue subtly about.
4. to make thin, rare, or more fluid or volatile;
   refine.

v.i. 

5. to make subtle distinctions or to argue subtly.

Also,[esp. Brit.,] sub′til•ise′. 

• Medieval Latin subtīlizāre, equivalent. to subtīl(is) subtle + -izāre -ize
• 1585–95

sub′til•i•za′tion, n. 
sub′til•iz′er, n. 

Collins Concise English Dictionary © HarperCollins Publishers::

subtilize, subtilise / ˈsʌtɪˌlaɪz/ verb

1. (transitive) to bring to a purer state; refine
2. to debate subtly
3. (transitive) to make (the mind, etc) keener

ˌsubtiliˈzation, ˌsubtiliˈsation noun