The term BASE TRUANT is composed of two words, BASE and TRUANT. BASE is an acronym for Basic Allowance for Subsistence and is a type of military pay given to members of the United States Armed Forces. TRUANT is a term used to describe someone who is absent without leave (AWOL), which is a four-letter acronym. In other words, BASE TRUANT is a term used to describe a member of the US Armed Forces who is absent without leave and receiving Basic Allowance for Subsistence.