tack up verb 2tack-up noun 1forms 4 verb2 •To attach in a temporary fashion (with or as if with tacks or pins), as for example to fix pieces of fabric into position in preparation for sewing their seams, or to hang dropcloths as masking before painting. •To prepare a horse for riding by equipping it with tack (harness, reins, saddle etc.) tack-up noun1 •A poster.Tack-ups serve for windows of miscellaneous shops, proprietors of these places being rewarded for their indulgence […] — 1916 formstacked up · tacking up · tacks up · tack-ups