From Longman Dictionary of Contemporary Englishuncharted/troubled/murky watersuncharted/troubled/murky watersformal a situation that is difficult, dangerous, or unfamiliar the uncharted waters of the 21st century → water
Examples from the Corpus
uncharted/troubled/murky waters• This is useful if you fly by night or live in murky waters.• Clearly the 49ers are sailing in uncharted waters.• And instead of heading off into uncharted waters, Shyamalan has positively invited comparisons with his previous opus.• Other career seekers are more interested in venturing into uncharted waters.• A fish that comes from slow-moving often murky waters is unlikely to appreciate bright lighting or turbulent filtration.• But then our conversations took a dive into the murky waters of sexuality and jealousy.• A last desperate attempt to escape into the murky waters.• I would be chary of anything caught in these murky waters. 