Definify.com

Webster 1828 Edition

Adj.

[L. subtilis. This word is often written subtle, but less properly.]

Thin; not dense or gross; as subtil air; subtil vapor; a subtil medium.

Nice; fine; delicate.

I do distinguish plain

Each subtil line of her immortal face.

Acute; piercing; as subtil pain.

Sly; artful; cunning; crafty; insinuating; as a subtil person; a subtil adversary.

Planned by art; deceitful; as a subtil scheme.

Deceitful; treacherous.

Refined; fine; acute; as a subtil argument.