Difference between Questionable and Alleged

QUESTIONABLE vs ALLEGED: ADJECTIVE

Able to be refuted
Open to doubt or challenge; problematic.
Not yet determined or specified.
Of dubious morality or respectability.
Admitting of being questioned; inviting, or seeming to invite, inquiry.
Liable to question; subject to be doubted or called in question; problematical; doubtful; suspicious.
Subject to question
Of dubious respectability or morality
Problematic; open to doubt or challenge

Capable of being questioned or inquired of; inviting or seeming to invite inquiry or conversation.
Liable to question; suspicious; doubtful; uncertain; disputable: as, the deed is of questionable authority; his veracity is questionable.

That is or has been stated to be (what is specified in the following word or clause); merely stated or asserted: much used when one wishes to disclaim responsibility for the statement, or to intimate his disbelief in it: as, an alleged fact; an alleged interview; an alleged illness.

Supposed, Apocryphal, Deniable, Suspect, Refutable, Alleged, Equivocal, Suspicious, Fishy, Problematical, Shady, Problematic, Debatable, Doubtful, Dubious

Complained, Charged, Complaint, Purportedly, Indicted, Claimed, Purported, Allegation, Suspected, Allegations, Accused, So called, Declared, Supposed, Questionable

Supposed, Apocryphal, Deniable, Suspect, Refutable, Alleged, Equivocal, Suspicious, Fishy, Problematical, Shady, Problematic, Debatable, Doubtful, Dubious

Complained, Charged, Complaint, Purportedly, Indicted, Claimed, Purported, Allegation, Suspected, Allegations, Accused, So called, Declared, Supposed, Questionable

Histopathology should be considered to discern questionable lesions.
Implement procedures for follow up on questionable cases.
Any questionable purchases are reimbursed by the employees.
The value of determining rectal temperature is questionable.
Report: Steph Curry, Kevin Durant questionable tomorrow vs.
Might some of those restrictions be constitutionally questionable?
The evidence behind this dietary strategy is questionable.
Propose removing this verbiage as it is questionable whether this is relevant given the amount of information available and possibly ethically questionable.
Do report coupons you see that look questionable by sending any valuable information you have about where you saw or received a questionable coupon.
We have software on all our electronics that alerts each other if we go to questionable sites or search questionable content, etc.

Belize City resident during an alleged robbery attempt.
Democrats alleged were aimed at suppressing minority voters.
Campus Judicial Board to discuss the alleged violations.
Alleged violations of these provisions will be investigated.
This letter sets forth the alleged violations, the evidence supporting the alleged violations, and the minimum steps necessary to correct the violations.
The claims alleged in these actions are substantially identical to the claims alleged in the consolidated federal securities class action described above.
The defense issued a subpoena duces tecum for the medical records of the victim of an alleged assault and an alleged battery.
In a legal context, prosecutors offer alleged criminals a lighter sentence in exchange for witness testimony against another alleged criminal facing more serious charges.
Defended an alleged gang member accused of having a sawn off shotgun which was alleged to have been used to threaten others.
Investigations will include interviews with the alleged target, the alleged bully, and any witnesses.