Wordnet 3.0
ADJECTIVE (2)
1. 
 capable of being assessed especially for the purpose of taxation; 
2. 
 capable of being considered carefully; 
- Example: "the assessable qualities of art"
The Collaborative International Dictionary of English v.0.48:
Assessable \As*sess"a*ble\, a.
   Liable to be assessed or taxed; as, assessable property.
   [1913 Webster]
WordNet (r) 3.0 (2006):
assessable
    adj 1: capable of being assessed especially for the purpose of
           taxation
    2: capable of being considered carefully; "the assessable
       qualities of art"