According to the documentation i can load a sense tagged corpus in nltk as such:
>>> from nltk.corpus import wordnet_ic >>> brown_ic = word
If you only need to know what the most frequent word is, you can do wn.synsets(word)[0] since WordNet generally ranks them from most frequent to least frequent.
wn.synsets(word)[0]
(source: Daniel Jurafsky's Speech and Language Processing 2nd edition)