Rationalize \Ra"tion*al*ize\, v. i. To use, and rely on, reason in forming a theory, belief, etc., especially in matters of religion: to accord with the principles of rationalism.

Theodore . . . is just considered the chief rationalizing doctor of antiquity. --J. H. Newman.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Rationalize \Ra"tion*al*ize\, v. t.

1. To make rational; also, to convert to rationalism.

2. To interpret in the manner of a rationalist.

3. To form a rational conception of.

4. (Alg.) To render rational; to free from radical signs or quantities.

Source: Webster's Revised Unabridged Dictionary (1913)