Webster's Revised Unabridged Dictionary · 1913

Merciful

Merciful , adjective

[Mercy + -ful.]

1.
Full of mercy; having or exercising mercy; disposed to pity and spare offenders; unwilling to punish. Opposite of merciless.
The Lord, the Lord God, merciful and gracious. — Ex. xxxiv. 6
Be merciful, great duke, to men of mold. — Shakespeare
2.
Unwilling to give pain; compassionate.
A merciful man will be merciful to his beast. — Old Proverb