adj. 25B6; adjective
a rigid container : STIFF, hard, firm, inflexible, unbending, unyielding, inelastic.
a rigid routine : FIXED, set, firm, inflexible, unalterable, unchangeable, immutable, unvarying, invariable, hard and fast, cast-iron.
a rigid approach to funding : STRICT, severe, stern, stringent, rigorous, inflexible, uncompromising, intransigent.
flexible, lenient.