蔑 is a bound form (b.f.) meaning 'disdain, scorn'. It cannot stand alone as an independent word; you must combine it with another character to form common two-syllable terms like 蔑视 ('to despise'), 轻蔑 ('contempt'), or 诬蔑 ('to slander'). When you learn 蔑, memorize it as a morpheme that only appears inside compound words — never use it by itself.