Removing banal words from a list

Please also see a related problem here, it might give you more ideas. Words can be banal wrt all words in the dictionary or wrt some particular list of words. Let's consider the later case. WordFrequencyData gives the frequency of word in typical published English text. Within a given list of words you can find the max-frequency word and rescale the rest of the words according to it. Then a threshold to cut off more popular words will be always between 0 and 1.

banal[w_,t_]:=With[{freq=WordFrequencyData[w]},
Keys[Select[freq/Max[freq],#<=t&]]]

For your set of words:

words={"exegesis", "mystification", "bread", "synthesis", 
"dog", "autonomy", "develop", "enthusiastic", "house"};

and threshold $0.1$ we get

In[]:= banal[words,.1]
Out[]= {exegesis,mystification,synthesis,autonomy,enthusiastic}

with the dropped words being:

In[]:= Complement[words,%]
Out[]= {bread,develop,dog,house}