illegitimately

Adverb

• of biological parents not married to each other
  • this child was born illegitimately
    

• in a manner disapproved or not allowed by custom
  • He acted illegitimately when he increased the rent fourfold
    

Related words

• Synonyms: 
  out of wedlock , illicitly
• Antonyms: 
  legitimately , lawfully , licitly