Homophones for gnaw, knaw, nah (naw)

gnaw / knaw / nah (naw) [nɔ] 

gnaw – v. – 1. slowly eat away at something; 2. corrode, break down by nibbling; 3. persistently worry

knaw – v. – variant of ‘know’- perceive, understand, recognize

nah (naw) – adv. & interj. – indicating a negative response