Lenity, n.
Etymology: [L. lenitas, fr. lenis soft, mild: cf. OF. lenité. See Lenient.]
The state or quality of being lenient; mildness of temper or disposition; gentleness of treatment; softness; tenderness; clemency; -- opposed to severity and rigor. His exceeding lenity disposes us to be somewhat too severe. Macaulay.
Syn. -- Gentleness; kindness; tenderness; softness; humanity; clemency; mercy.
Shades of meaning
Fernald has no entry of its own for lenity; he lists it under mercy.
Where he writes about it:
Leniency or lenity denotes an easy-going avoidance of severity; these words are more general and less magisterial than clemency; we should speak of the leniency of a parent, the clemency of a conqueror. — from mercy