'far' is an adjective and 'from' is a preposition.
'true' can sometimes be used as a noun according to dictionary.com, so in the phrase 'it is far from X' X seems to always be a noun. For example,
'It is far from large.' doesn't sound very natural to me (a native speaker). It is understandable though.
I recommend always using a noun in this particular phrase.
Student or Learner