7 letters · 8 points in Scrabble
verb place under suspicion or cast doubt upon
verb make dirty or spotty, as by exposure to air; also used metaphorically
verb charge falsely or with malicious intent; attack the good name and reputation of someone
originFrom sully + -ied (suffix forming participial adjectives and past participal forms of verbs ending in -y).
Etymology from Wiktionary, CC BY-SA 3.0