The Collaborative International Dictionary of English v.0.48:

Lenience \Le"ni*ence\ (l[=e]"n[i^]*ens or l[=e]n"yens; 106),
Leniency \Le"ni*en*cy\ (l[=e]"n[i^]*en*s[y^] or
   l[=e]n"yen*s[y^]), n.
   The quality or state of being lenient; lenity; clemency.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lenience
    n 1: mercifulness as a consequence of being lenient or tolerant
         [syn: lenience, leniency, mildness, lenity]
    2: a disposition to yield to the wishes of someone; "too much
       indulgence spoils a child" [syn: indulgence, lenience,
       leniency]
    3: lightening a penalty or excusing from a chore by judges or
       parents or teachers [syn: lenience, leniency]