1684 (v.) "to assume a formal, precise demeanor," probably from Fr. prim
"thin, small, delicate," from O.Fr. prim
"fine, delicate," from L. primus
"first, finest" (see prime
). Attested as a noun from 1700. The adj., the sole surviving sense, is from 1709. A cant word at first; the noun sense may be the original.