Somewhat sharp or acid in character: subacid remarks. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "subacid" in a sentence
"As to her person, she had a neat oval face, thin and sallow, in expression subacid; a lithe, rather graceful figure, and hands too long, with fingers almost too tapering -- of which hands and fingers she was very careful, contemplating them in secret with a regard amounting almost to reverence: they were her sole witnesses to a descent in which she believed, but of which she had no other shadow of proof."
"The fruits are usually insipid, occasionally subacid or acid."
"Lansats, two of the most delicious of the subacid tropical fruits."