Sardonic
a.-
Forced; unnatural; insincere; hence, derisive, mocking, malignant, or bitterly sarcastic; -- applied only to a laugh, smile, or some facial semblance of gayety.
an old medical term for a spasmodic affection of the muscles of the face, giving it an appearance of laughter.
a.
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Of, pertaining to, or resembling, a kind of linen made at Colchis.