Clues for the word "INDURATE"

We've had 2 crossword clues used for this word, and seen it 2 times in crosswords. It was last seen in USA Today crossword on September 23, 2015.

Definition of indurate

a. - Hardened; not soft; indurated.
a. - Without sensibility; unfeeling; obdurate.
v. t. - To make hard; as, extreme heat indurates clay; some fossils are indurated by exposure to the air.
v. t. - To make unfeeling; to deprive of sensibility; to render obdurate.
v. i. - To grow hard; to harden, or become hard; as, clay indurates by drying, and by heat.