parathesis /pə-rathˈi-sis/

1. Apposition (grammar)
2. The compounding of words without change, as (Latin) rēspūblica from rēs and pūblica (philology)

• underbid
• underbidder
• underbidders
• underbidding
• underbids
• underbit
• underbite
• underbites
• underbiting
• underbitten
• underblanket
• underblankets
• under-board
• underbodies
• underbody
• under-bonnet
• underbore
• underborne
• underbough
• underboughs
• underbought
• under-boy
• under-boys
• underbreath
• underbreaths