atavistic (adj.)

• aboriginal
• ancestral
• autochthonous
• bodily
• born
• coeval
• congenital
• connate
• connatural
• constitutional
• genetic
• hereditary
• inborn
• inbred
• incarnate
• indigenous
• inherited
• innate
• instinctive
• native
• natural
• organic
• patriarchal
• physical
• prehistoric
• primal
• prime
• primeval
• primitive
• primordial
• pristine
• reactionary
• recessive
• regressive
• retrograde
• retrogressive
• retrorse
• returnable
• reversible
• reversionary
• revertible
• temperamental