Inflexible may refer to: Stiffness, the rigidity of an object, the extent to which it resists deformation in response to an applied force Beardmore Inflexible, a British three-engined all-metal prototype bomber aircraft of the 1920s HMS Inflexible, one of several Royal Navy ships of this name Inflexible-class ship of the line built for the Royal Navy in the late 16th century French submarine Inflexible (S615), a French nuclear submarine LMS Jubilee Class 5727 Inflexible, a steam locomotive constructed in 1936. ST Inflexible, a French tugboat See also Flexibility (disambiguation)