title: Python NLTK Lemmatization of the word 'further' with wordnet
body: <p>I'm working on a lemmatizer using python, NLTK and the WordNetLemmatizer.
  Here is a random text that output what I was expecting</p>
  
  <pre><code>from nltk.stem import WordNetLemmatizer
  from nltk.corpus import wordnet
  lem = WordNetLemmatizer()
  lem.lemmatize('worse', pos=wordnet.ADJ) // here, we are specifying that 'worse' is an adjective
  </code></pre>
  
  <p>Output: <code>'bad'</code></p>
  
  <pre><code>lem.lemmatize('worse', pos=wordnet.ADV) // here, we are specifying that 'worse' is an adverb
  </code></pre>
  
  <p>Output: <code>'worse'</code></p>
  
  <p>Well, everything here is fine. The behaviour is the same with other adjectives like <code>'better'</code> (for an irregular form) or <code>'older'</code> (note that the same test with <code>'elder'</code> will never output <code>'old'</code>, but I guess that wordnet is not an exhaustive list of all the existing english word)</p>
  
  <p>My question comes when trying with the word <code>'furter'</code>:</p>
  
  <pre><code>lem.lemmatize('further', pos=wordnet.ADJ) // as an adjective
  </code></pre>
  
  <p>Output: <code>'further'</code></p>
  
  <pre><code>lem.lemmatize('further', pos=wordnet.ADV) // as an adverb
  </code></pre>
  
  <p>Output: <code>'far'</code></p>
  
  <p>This is the exact opposite behaviour of the one for the <code>'worse'</code> word!</p>
  
  <p>Can anybody explain me why ? Is it a bug coming from the wordnet synsets data or does it come from my misunderstanding of the english grammar ?</p>
  
  <p>Please excuse me if the question is already answered, I've search on google and SO, but when specifying the keyword "further", I can find anything related but mess because of the popularity of this word...</p>
  
  <p>Thank you in advance,
  Romain G.</p>