flak vs unfavorable judgment

flak and unfavorable judgment both are nouns.

Word	Noun	Adjective	Verb	Adverb
flak	Yes	No	No	No
unfavorable judgment	Yes	No	No	No

As nouns, unfavorable judgment is a hypernym of flak; that is, unfavorable judgment is a word with a broader meaning than flak:

flak: intense adverse criticism
unfavorable judgment: disapproval expressed by pointing out faults or shortcomings

Other hypernyms of flak include criticism.

flak (noun)	unfavorable judgment (noun)
artillery designed to shoot upward at airplanes	disapproval expressed by pointing out faults or shortcomings
intense adverse criticism
a slick spokesperson who can turn any criticism to the advantage of their employer