The Collaborative International Dictionary of English v.0.48:

Roger \Rog"er\, n. [From a proper name Roger.]
   A black flag with white skull and crossbones, formerly used
   by pirates; -- called also Jolly Roger and pirate flag.
   [Webster 1913 Suppl. +PJC]

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "Roger":
   OK, absolutely, all right, alright, alrighty, amen, as you say,
   assuredly, aye, by all means, certainly, da, exactly, fine, good,
   good enough, hear, indeed, indeedy, ja, just so, mais oui,
   most assuredly, naturally, naturellement, of course, okay, oui,
   positively, precisely, quite, rather, really, right, righto, sure,
   sure thing, surely, to be sure, truly, very well, well and good,
   why yes, yea, yeah, yep, yes, yes indeed, yes indeedy, yes sir,
   yes sirree