The Collaborative International Dictionary
Subtiliate
Subtiliate \Sub*til"i*ate\, v. t. [LL. subtiliare.]
To make thin or rare. [Obs.]
--Harvey. -- Sub`til*i*a"tion,
n. [Obs.]
--Boyle.
Wiktionary
subtiliate
vb. (context obsolete transitive English) To make thin or rare; to rarefy.