fretless adjective 2noun 1forms 1 adjective2 •Of a stringed instrument, not having frets on the fingerboard. •Without worries.You would live longer and happier if you would only be quiet and fretless. — 1895 noun1 •A stringed instrument without frets on the fingerboard.Read's creations have covered just about all of bass-dom, from vintage-style 4-strings to 32-position fretlesses to 25-fret 8-strings tuned F♯BEADGCF. — 2003 formsfretlesses