WordNet (r) 3.0 (2006):

well-to-do
    adj 1: in fortunate circumstances financially; moderately rich;
           "they were comfortable or even wealthy by some
           standards"; "easy living"; "a prosperous family"; "his
           family is well-situated financially"; "well-to-do members
           of the community" [syn: comfortable, easy,
           prosperous, well-fixed, well-heeled, well-off,
           well-situated, well-to-do]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "well-to-do":
   abounding in riches, affluent, big-rich, comfortable,
   disgustingly rich, easy, fat, flush, frightfully rich, in funds,
   in the money, independent, independently rich,
   independently wealthy, loaded, luxurious, made of money, moneyed,
   oofy, opulent, prosperous, provided for, rich, rich as Croesus,
   rolling in money, snug, substantial, wallowing in wealth, warm,
   wealthy, well, well provided for, well-fixed, well-heeled,
   well-off