watertight

As adjectives the difference between raintight and watertight

is that raintight is so tight as to exclude rain while watertight is so tightly made that water cannot enter or escape.

As adjectives the difference between watertight and watertight

is that watertight is so tightly made that water cannot enter or escape while watertight is so tightly made that water cannot enter or escape.

As adjectives the difference between foolproof and watertight

is that foolproof is for a device: protected, or designed to be proof against misuse or error; fail-safe while watertight is so tightly made that water cannot enter or escape.

As a verb foolproof

is {{cx|transitive|lang=en}} To make foolproof.

As adjectives the difference between rainproof and watertight

is that rainproof is (of external clothing) waterproof while watertight is so tightly made that water cannot enter or escape.

As a verb rainproof

is to make rainproof.

As adjectives the difference between watertight and impermeable

is that watertight is so tightly made that water cannot enter or escape while impermeable is waterproof.

As a noun impermeable is

raincoat.

As adjectives the difference between watertight and hermetic

is that watertight is so tightly made that water cannot enter or escape while hermetic is (chiefly with capital initial) pertaining to (hermes trismegistus) or the writings attributed to him.

As a noun hermetic is

(in plural) hermetic philosophy or practice.

As a noun caisson

is (engineering) an enclosure, from which water can be expelled, in order to give access to underwater areas for engineering works etc.

As an adjective watertight is

so tightly made that water cannot enter or escape.

As adjectives the difference between weatherproof and watertight

is that weatherproof is capable of resisting damage caused by the weather while watertight is so tightly made that water cannot enter or escape.

As a verb weatherproof

is to make something resistant to damage caused by the weather.