F4L1A1T1
7 points
FLAT is validvalid
having a smooth or even surface [adj FLATTER, FLATTEST] : FLATLY [adv], FLATNESS [n] / to make flat [v FLATS, FLATTED, FLATTING]
to make flat [v FLATTED, FLATTING, FLATS] / having a smooth level surface [adj FLATTER, FLATTEST, FLATLY]