Criticize, reprehend, blame, censure, reprobate, condemn, denounce are comparable when they mean to find fault with someone or something openly, often publicly, and with varying degrees of severity.
Criticize in its basic sense does not carry faultfinding as its invariable or even major implication; rather it suggests a discernment of the merits and faults of a person or thing.
In ordinary use, however, the word does commonly imply an unfavorable judgment or a pointing out of faults and is probably the term most frequently used to express this idea.
Reprehend in present-day English takes a person as an object far less often than a thing, a quality, or an action. In such use it not only explicitly suggests the approach of a critic and his disapproval but implies a more or less severe rebuke.
Blame fundamentally implies speaking in dispraise of a person or thing rather than in his or its favor; in general it also suggests the mental approach of a critic or detector of faults.
Blame sometimes loses much of its opposition to praise and then may strongly convey an imputation or accusation of wrongdoing or of guilt.
Again blame may connote ultimate responsibility rather than actual guiltiness and then can take a thing as well as a person for its object.
Since blame no longer invariably implies the simple reverse of commendation, censure is usually preferred to blame as the antonym of praise. This word carries a stronger suggestion of authority or competence in the critic or judge than does blame, as well as a clearer connotation of reprehension or, sometimes, of a reprimand.
Reprobate is often used as though it were a close synonym of reproach or rebuke.
Distinctively, however, it may imply not only strong disapproval and, usually, vigorous censure but also a rejection or a refusal to countenance.
Condemn carries even stronger judicial connotations than censure, for it implies a final decision or a definitive judgment; it commonly also suggests an untempered judgment which is wholly unfavorable and merciless.
Denounce adds to condemn the implication of public declaration or proclamation.