remprop

(remprop symbol indicator)

Removes the indicator property from the symbol's property list, returning true when it was there and nil when it was not. The partner of get / (setf (get ...)) and symbol-plist: all four read the one program-global, name-keyed store (symbols have no identity cells to hang plists on). Common Lisp only promises a generalized boolean here; this returns t, where some implementations return the plist tail.