watertight vs unshakable

watertight and unshakable both are adjectives.

Word	Noun	Adjective	Verb	Adverb
watertight	No	Yes	No	No
unshakable	No	Yes	No	No

As adjectives, watertight and unshakable are synonyms defined as:

Other synonyms of watertight include bulletproof, ironclad, unassailable.

watertight (adjective)	unshakable (adjective)
without flaws or loopholes	without flaws or loopholes
not allowing water to pass in or out	marked by firm determination or resolution; not shakable