late 15c., from un- (1) "not" + past participle of trouble (v.).
untroubled sleep
seemed untroubled by doubts of any kind
a kind untroubled face
untroubled times
untrained
untrammeled
untreatable
untried
untrodden
untroubled
untrue
untrustworthy
untruth
unturned
untwist
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