Wordnet 3.0
NOUN (1)
1. 
 the removal of constraints; 
- Example: "he gave free rein to his impulses"- Example: "they gave full play to the artist's talent"[syn: free rein, play]
WordNet (r) 3.0 (2006):
free rein
    n 1: the removal of constraints; "he gave free rein to his
         impulses"; "they gave full play to the artist's talent"
         [syn: free rein, play]