Stiff, rather than flexible.
Fixed, rather than moving.
Uncompromising.
Rigorous and unbending.
An airship whose shape is maintained solely by an internal and/or external rigid structural framework, without using internal gas pressure to stiffen the vehicle (the lifting gas is at atmospheric pressure); typically also equipped with multiple redundant gasbags, unlike other types of airship.
A bicycle with no suspension system.
Not held firmly in position, physically unstable.
Inconstant in purpose, or volatile in behavior.
Lacking regularity or uniformity.
To render unsteady, removing balance.