Without more context, I cannot pin down which word or phrase it is you are
thinking of, for there are endless ways to describe those individuals who
“let no slight go unanswered” that risks sullying their self-assessed awesomeness — be it real or imagined, trivial or extreme.
Countless multiword possibilties ranging from biting phrases to hackneyed
refrains can easily be found for this. In the arena of single words, there
can be nouns for those people, or adjectives describing them or their
activities, or verbs characterizing their habitual reaction. Often there
will be a cluster of a noun and verb and adjective, where one or two of
those derives from the third.
Here are a few nouns and adjectives that come quickly to mind; I give only one form but often there are closely related derived terms for the other parts of speech. For the sake a
uniformity of treatment and convenience, all citations are from Wiktionary.
- apologist: One who speaks or writes in defense of a faith, a cause, or an institution.
- (obsolete) That captures; especially, (of an argument, words etc.) designed to capture or entrap in misleading arguments; sophistical.
- Having a disposition to find fault unreasonably or to raise petty objections; cavilling, nitpicky
- cavilling: To criticise for petty or frivolous reasons.
- hypercritical: Meticulously or excessively critical.
- hyperdefensive: Extremely defensive (=Displaying an inordinate sensitivity to criticism).
- megalomaniacal: of, exhibiting, or affected with megalomania (=A psychopathological condition characterized by delusional fantasies of wealth, power, or omnipotence.)
- mother hen: (idiomatic) An outspoken and overprotective woman or person dealing with others' affairs.
- myrmidon: A soldier or a subordinate civil officer who executes orders of a superior without protest or pity (sometimes applied to bailiffs, constables, etc).
- Having an inflated idea of one's own importance.
- Obsessed with one's own self image and ego.
- overprotective: excessively protective, wanting to give too much protection (especially to children)
- pettifogger: Someone who quibbles over trivia, and raises petty, annoying objections.
- querulous: Often complaining; suggesting a complaint in expression; fretful, whining.
- self-obsessed: Deeply interested in oneself to the exclusion of others; vain and narcissistic; egotistical.
- spin doctor: (business, politics) A person employed to gloss over a poor public image (or present it in a better light) in business and politics, especially after unfavourable results have been achieved. A lobbyist; PR person.
- spinmeister: (US, politics, slang) A media liaison or spokesperson, charged with presenting the spin for their political side.
- tetchy: Easily annoyed or irritated; peevish, testy or irascible.
- thin-skinned: (idiomatic) overly sensitive to criticism; quick to take offence; irritable; touchy
- vituperator: One who vituperates, or censures abusively.