Wordnet 3.0
ADJECTIVE (2)
1. 
 being or marked by or containing or functioning as a consonant; 
- Example: "consonantal sounds"- Example: "a consonantal Hebrew text"- Example: "consonantal alliteration"- Example: "a consonantal cluster"2. 
 relating to or having the nature of a consonant; 
The Collaborative International Dictionary of English v.0.48:
Consonantal \Con`so*nan"tal\, a.
   Of the nature of a consonant; pertaining to consonants.
   [1913 Webster]
WordNet (r) 3.0 (2006):
consonantal
    adj 1: being or marked by or containing or functioning as a
           consonant; "consonantal sounds"; "a consonantal Hebrew
           text"; "consonantal alliteration"; "a consonantal
           cluster" [ant: vocalic]
    2: relating to or having the nature of a consonant