لُّمَزَةٍ

A word in the Arabic language will either be 1) a verb or 2) a noun or 3) a particle – لُّمَزَةٍ is a noun

A noun may either be 1) Definite or indefinite 2) Masculine or feminine 3) Singular, dual or plural 4) Nominative, accusative or genitive

لُمَزَةٌ is the natural state of this indefinite noun and it becomes لُمَزَةٍ due to: 1) a preposition that precedes it or 2) a possessed noun that precedes it or 3) it’s a noun of dependent declension a) نَعْتٌ / صِفَطٌ adjectives b) التَّوْكِيْدُ emphatic c) المَعْطُوْفٌ conjunction d) البَدَلُ synonym

لُمَزَةٍ takes a tanween to become لُّمَزَةٍ due to the indefinite, genitive noun preceding it in the sentence

Slanderer, backbiter, traducer, faultfinder, one who maliciously tries to uncover real or imaginary faults in others behind their back or before their eyes

To wink, make a sign with the eye or hand, defame, reproach, speak ill, strike, repel, traduce