aliphatic
al.i.phat.ic \.al-*-'fat-ik\ aj [ISV, fr. Gk aleiphat-, aleiphar oil, fr. aleiphein to smear;] akin to Gk lipos fat - more at LEAVE : of, relating to, or derived from fat; specif : belonging to a g roup of organic compounds having an open-chain structure and consisting of the paraffin, olefin, and acetylene hydrocarbons and their derivatives