Lewis & Short

sĭremps (sĭrempse, Plaut. Am. prol. 73), adj. [acc. to Fest. pp. 344 and 345 Müll., contr. from similis re ipsā, qs. simrepsa, simrepse, and by transposition, sirempse; but prob. from si-, loc. form from pronom. stem sa-, cf. sic; rem is acc. of reference, cf. prope-diem, pri-dem; -pe is the intens. part., as in nem-pe, etc., and becomes pse, with enclit. se, as in ipse, etc., v. Corss. Ausspr. 2, 846 sq.]; publicists’ t. t., of a like application of laws, like, the same: sirempse legem jussit esse Juppiter, Plaut. Am. prol. 73: siremps lex, S. C. ap. Front. Aquaed. 129; so Tab. Bantina, C. I. L. 197, 13; cf. id. 198, 73; 200, 27; 202, 1; 202, 38; 205, 2 al.; Lex ap. Grut. 508, 21; 628 fin.; 629, 1; Cato ap. Fest. 1. 1.: omnium quae terram premunt, siremps, lex esto, Sen. Ep. 91, 16; cf. Marin. Fratr. Arval. p. 568.