1. criticize: discuss critically (work, or abs.).
2. criticize: express disapproval of.
Both definitions stem from Oxford dictionaries, the major difference being that the first was published in 1977, the second in 2010. In those years, readers, writers, listeners, and the general public have learned the word to mean something negative, something innately bad. So we invented constructive criticism. According to my dictionary, constructive can also mean inferred, not directly expressed—we are now stuck giving helpful feedback while inferring what we really mean; we cloak the truth because the proud presenter is too soft-skinned to face some honest commentary. Quoting David Foster Wallace, if you're worried that criticize will seem too deprecatory, you can say evaluate, explicate, analyze, judge . . . (taken from the Oxford English Dictionary).
People try too hard to make criticism some kind of offense, as if we cannot criticize without offending; the two are inseparable. But true criticism is something worth savoring, something not meant to attack but to improve, investigate, discuss critically—you are, in fact, allowed to say something positive. Yet any modern humanities class focused on student output claims against such a definition and requires instead constructive feedback, which, in writing class, means explaining why the writer sucks without saying it. Constructive feedback is just that: a wordy alternative to criticism that reads like the auditory equivalent of petting a donkey while nailing its tail to a yard post.
Now let's all say something nice.
1. The Concise Oxford Dictionary (London: Book Club Associates, 1977), 243.
2. Pocket Oxford American Dictionary & Thesaurus (New York: Oxford University Press, 2010), 180.