A boat that can go underwater.
A kind of sandwich made in a long loaf of bread.
Pitch delivered with an underhand motion.
Any submarine plant or animal.
A stowaway on a seagoing vessel.
To operate or serve on a submarine.
To torpedo; to destroy with a sudden sneak attack.
(sometimes figurative) To sink or submerge oneself.
Undersea.
Hidden or undisclosed.
Of a pitch, thrown with the hand lower than the elbow.