excuser

One who offers excuses or pleads in extenuation of the fault of another.

In vain would his excusers endeavour to palliate his enormities, by imputing them to madness; because it is well known, that madness only operates by inflaming and enlarging the good or evil dispositions of the mind.

One who excuses or forgives another.

yet love is a sufficient excuse and excuser of greater errors than are mine