unfoundedun‧found‧ed /ʌnˈfaʊndɪd/ ●○○ AWL adjective 
Unfounded rumours began circulating that Ian and Susan were having an affair.prove (to be) unfounded Sadly, my optimism proved unfounded.
EXAMPLES FROM OTHER DICTIONARIES
- All the signs indicate that the general's optimism is unfounded.
- I am going to prove to you that your suspicions are entirely unfounded
- Suspicions of a government cover-up are entirely unfounded.
- He could hear his piping London voice with its parrot greetings and unfounded optimism.
- It turned out that my suspicions were unfounded, but all the time my memories were coming back.
- Much of this toll is preventable, including that related to unfounded fears of infection.
- Of the 40,000 asylum applications made last year, nine out of 10 were unfounded.
- They had hoped those fears would prove unfounded yesterday, but the rhetoric only got more vituperative.
- We are amazed that a fellow professional has stooped so low as to make such unfounded comments in the papers.
Longman Language Activatorwhen there is no reason for someone's behaviour
use this to say that there is no reason for someone to think or behave in a particular way: be no reason to do something: · I know I'm late, but that's no reason to lose your temper.there is no reason for something: · Please remain calm everyone. There is no reason for panic.
use this to say that there is no acceptable reason for someone to think or behave in a bad or unfair way. Be no justification is more formal than be no excuse: · "But she started it." "That's no excuse."be no excuse/justification to do something: · Ron may not be the most pleasant person to work with, but that's no justification to fire him.there's no excuse/justification for something: · There's no excuse for such childish behaviour from a grown man.
groundless fears, suspicions etc that are unnecessary because there are no facts to base them on: · Fleury dismissed our fears as groundless, though he was secretly alarmed.· A message from Interpol confirmed that our Inspector's suspicions were far from groundless.
worries, fears, hopes etc that are unfounded are wrong because there are no reasons to have these feelings: · I am going to prove to you that your suspicions are entirely unfounded.· All the signs indicate that the general's optimism is unfounded.
COLLOCATIONS FROM THE ENTRY Unfounded rumours began circulating that Ian and Susan were having an affair. Sadly, my optimism proved unfounded.COLLOCATIONS FROM OTHER ENTRIES
unfounded statements, feelings, opinions etc are wrong because they are not based on factsunfounded rumours/claims/allegations etc Unfounded rumours began circulating that Ian and Susan were having an affair. Sadly, my optimism proved unfounded. (=not based on facts or reason)· The accusation is totally unfounded.· The embassy denied what it called groundless accusations about its involvement in the attack.
(=not based on truth or evidence)· These claims of discrimination are completely unfounded.
· He says that the rumours are completely unfounded.· False rumors began to spread that troops were massing on the border.
(=there is no reason to worry)· Fortunately their worries were unfounded and the astronauts returned safely to Earth.
COLLOCATIONS FROM THE CORPUSADVERB· He might find them totally unfounded.· We now realise that these claims are totally unfounded.
NOUN· We need to be able to determine accurately and fairly those with unfounded claims.· This implies that everything listed as a mental disorder in the handbook has a biological contribution, a patently unfounded claim.
· They lived in the same apartment block and often dined together, creating unfounded rumours that they were having an affair.
Unfounded rumours began circulating that Ian and Susan were having an affair.prove (to be) unfounded Sadly, my optimism proved unfounded.