"rather stiff," 1858, a dictionary word, as if from a diminutive of Latin rigidus (see rigid).
Entries linking to rigidulous
rigid adj.
"stiff, unyielding, inflexible, firm, not easily bent," early 15c., from Latin rigidus "hard, stiff, rough, severe," from rigēre "be stiff" (from PIE root *reig- "stretch; be stretched; be stiff"). Related: Rigidly. As a verb, "to make rigid," rigidize is attested by 1944 in U.S. military and commercial use in reference to metals; earlier was rigidify (1842), rigidification.