primeval or primaeval /prī-mēˈvl/

1. Belonging to the earth's beginnings
2. Primitive
3. Instinctive

• understratum
• understudied
• understudies
• understudy
• understudying
• undersubscribed
• undersupplies
• undersupply
• undersurface
• undersurfaces
• under suspicion
• underta'en
• undertakable
• undertake
• undertaken
• undertaker
• undertakers
• undertakes
• undertaking
• undertakings
• undertane
• undertenancies
• undertenancy
• undertenant
• undertenants