Entry 1 sense Webster, 1913 Let-off /(lĕt"ŏf`; 115)/ · Let·-off · IPA 01 n. A device for letting off, releasing, or giving forth, as the warp from the cylinder of a loom. 1. A device for letting off, releasing, or giving forth, as the warp from the cylinder of a loom.(Mach.)