As nouns the difference between gabardine and twill
is that gabardine is a type of woolen cloth with a diagonal ribbed texture on one side while twill is a pattern, characterised by diagonal ridges, created by the regular interlacing of threads of the warp and weft during weaving.
As a verb twill is
to weave (cloth, etc.) so as to produce the appearance of diagonal lines or ribs on the surface.