Definition of Nice Nelly in English:

Nice Nelly

(also Nice Nellie, nice Nelly)

noun

North American
informal, depreciative
  • A person who is excessively concerned with maintaining an appearance of propriety or respectability; a prudish or fastidious person.

adjective

North American
informal, depreciative
  • Prudish, fastidious; overly concerned with respectability.

Origin

1920s; earliest use found in The Boston Globe. From nice + Nellie, Nelly, pet-form of the female forenames Eleanor and Helen.

Pronunciation

Nice Nelly

/ˌnʌɪs ˈnɛli/