مؤثر

 mu`as̤s̤ir (act. part. of أثّر 'to leave or make a mark, or impression, etc. (upon),' ii of أثر 'to make a mark in, or on,' etc.), part, adj. Making an impression; penetrating; taking effect; efficacious, effective, efficient, effectual; striking; applicable;—affecting, touching:—mu`as̤s̤ar (pass. part. of the same verb), part. Impressed (upon); penetrated; affected (by):—mu`as̤s̤ir honā(with loc.), To prove efficacious, to have effect, etc. (i.q. as̤ar karnā, q.v.).