WordNet (r) 3.0 (2006):

mensch
    n 1: a decent responsible person with admirable characteristics
         [syn: mensch, mensh]

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "mensch":
   acceptable person, capital fellow, diamond, gem, gentleman,
   good fellow, good lot, good man, good person, good sort,
   good woman, honest man, jewel, lady, pearl, perfect gentleman,
   perfect lady, persona grata, prince, real man, right sort,
   rough diamond, worthy