1. In a manner disapproved or not allowed by custom
   - illegitimately 
2. In an illegal manner
   - illegally, lawlessly

See also: illicit

Antonym: licitly

• insensitively
• insensitiveness
• insensitivity
• insentience
• insentient
• inseparability
• inseparable
• inseparableness
• inseparably
• insert
• insertion
• insertional mutagenesis
• Insessores
• inset
• inshallah
• inshore
• inside
• inside caliper
• inside clinch
• inside information
• inside job
• inside leg
• inside loop
• Inside Passage
• inside track