9 letters · 14 points in Scrabble
verb provide furniture with padding, springs, webbing, and covers
originBack-formation from upholsterer (“tradesman who finishes furniture”), from Middle English upholdester, variant of Middle English upholder (“dealer in small goods”), from upholden (“to repair, uphold”); equivalent to uphold + -ster. Sense development as well as form may have been influenced by conflation with unrelated bolster.
Etymology from Wiktionary, CC BY-SA 3.0