fiber

1 the strength of mind that enables a person to endure pain or hardship a person of lesser fiber would not have spoken out against such an injustice Synonyms backbone, constancy, fortitude, grit, grittiness, guts, intestinal fortitude, pluck, spunkRelated Words determination, purposefulness, resoluteness, resolution; bravery, courage, courageousness, daring, dauntlessness, doughtiness, fearlessness, gallantry, greatheartedness, intrepidity, intrepidness, nerve, stoutness, valor; endurance, forbearance, stamina, sufferance, tolerance; heart, mettle, spirit; audacity, boldness, brass, cheek, chutzpah (also chutzpa or hutzpah or hutzpa), effrontery, gall, hardihood, nerve, nerviness, temerityNear Antonyms indecisiveness, irresoluteness, irresolution, vacillation; cowardice, cowardliness, cravenness, dastardliness, faintheartedness, pusillanimity, timidity, timorousnessAntonyms spinelessness

2 a thin, flexible structure that resembles a hair the fibers found on the victim's body came from a carpet in the suspect's home Synonyms bristle, hair, filament, threadRelated Words microfiber; cord, rope, string, wire, yarn; fuzz, tuft