If you want the synonyms in the synset (i.e.aka the lemmas that make up the set), you can get them with lemma_names():
>>> for ss in wn.synsets('small'): >>> print(ss.name(), ss.lemma_names()) small.n.01 ['small'] small.n.02 ['small'] small.a.01 ['small', 'little'] minor.s.10 ['minor', 'modest', 'small', 'small-scale', 'pocket-size', 'pocket-sized'] little.s.03 ['little', 'small'] small.s.04 ['small'] humble.s.01 ['humble', 'low', 'lowly', 'modest', 'small'] ...