"Killer" subs are designed to "kill" other subs. They're distinguished from nuclear missile subs, and from subs used mainly for scouting and transport.
> "Killer" subs are designed to "kill" other subs. They're distinguished from nuclear missile subs
Isn't that what I said?
> and from subs used mainly for scouting and transport
For actual navies (as opposed to for example drug smugglers) scouting and transport (which is super-niche) is done by hunter killer submarines - they aren't a separate thing.
The 'largely around coastal waters' (littoral) should hint at this.