From Longman Dictionary of Contemporary Englishsub-aquasub-aq‧ua /sʌb ˈækwə/ adjective [only before noun] British EnglishDLO relating to sports that take place under water sub-aqua diving
Examples from the Corpus
sub-aqua• Cheap swimming goggles fit Whopperbears but don't let it be tempted to go sub-aqua!• Cousteau's An original seafood restaurant with sub-aqua atmosphere.• Of course we don't carry sub-aqua gear to check out these features before fishing: we can only discover them through practice. 