prob-, proba-, probat-, prov-

(Latin: upright, good, honest; to try, to test, to examine; to demonstrate)

reprobation
1. Severe disapproval; disreputabl.
2. Strong condemnation or disapproval of somebody or something.
reproof
1. An act or expression of criticism and censure.
2. To censure or rebuke severely or angrily.
reprovable (adjective), more reprovable, most reprovable
1. Deserving of reproach: Jack's reprovable and critical utterance was heard throughout the office.
2. Worthy of censure; blameworthy: Mrs. Smart didn't put up with any reprovable conduct among the students in her classroom, and she scolded them severely if they misbehaved.
reprove, reproves, reproved, reproving (verbs)
1. To voice or to convey disapproval of; to rebuke.
2. To find fault with; to admonish.
unimprovable (adjective) (not comparable
Not disposed to melioration or betterment: Over the years Mildred's handwriting proved to be unimprovable although she tried her best to make it more readable.
unimproved
1. Not developed to full potential, as resources or the mind.
2. Not showing improvement, as regards to one's health, appearance, etc.
3. With reference to land, not fitted for a profitable use, as by clearing, cultivation, addition of facilities for dwelling or business purposes, etc.
4. Not used to advantage; neglected.
5. With animal or plant species; not made more useful or attractive by selective breeding or cultivation.
6. Not enhanced; not increased: "His chances of success are unimproved."
unreproved
1. Not rebuked for a fault or misdeed.
2. Not subjected to reproof or rebuke.