What is the full meaning of snub?

1 : to check or stop with a cutting retort : rebuke. 2a : to check (something, such as a line or chain that is running out) suddenly especially by turning around a fixed object (such as a post or a cleat) also : to check the motion of by snubbing a line snub the anchor.

What does it mean when something is watertight?

1 : of such tight construction or fit as to be impermeable to water except when under sufficient pressure to produce structural discontinuity. 2 : leaving no possibility of misconstruction or evasion a watertight lease.