No. Unflattering is an adjective.A prefix is a word part. It is added to a word to change or modify its meaning. (E.g. the prefix un- added to flattering forms the new and opposite word unflattering.)
Scalawag
Fluorescent lights!
Scalawag.
Dishonesty
Poo bar
showing or representing unfavorably; "an unflattering portrait"; "an uncomplimentary dress".
Smelliest
Adversarial press is a style of journalism where journalists adopt a critical and confrontational approach towards those in power. It involves questioning authority, holding officials accountable, and exposing wrongdoing to serve the public interest. This type of journalism aims to challenge the status quo and ensure transparency in governance.
Because he is afraid you will tell his current girlfriend some unflattering things about him.
An English cricketer - if you are being polite - or some unflattering name if he has just played badly!
Retouching means removing unwanted/unflattering objects, or enhancing certain parts of an image.