An adjective
"when" is ADVERB (interrogative & relative).
adverb
it can be a noun, adjective, or adverb. visit dictionary.com to find out which one kind you are using
what part of speech is beneath
i want to know what part of speech is camping
Kind is an adjective.
From is a preposition.
It turns out that Hitler's lair was not impregnable.
impregnable = de necucerit
The part of speech that answers the question "what kind" is an adjective. Adjectives describe or modify nouns and pronouns by providing information about their qualities or characteristics.
In Karate I am impregnable to catch my partners fist.
"Impregnable" means unable to be captured or entered by force, as in a fortress or stronghold. The prefix "im-" in "impregnable" is a negative prefix, meaning "not" or "without," so "impregnable" essentially means "cannot be penetrated."
"when" is ADVERB (interrogative & relative).
The Maginot Line was thought to be impregnable. The hardened titanium alloy made the door impregnable to the battering ram.
A noun; it is a particular kind of tree.
A noun; it is the name of a kind of flower.
Something that cannot be penetrated or destroyed, such as, "The fortress was impregnable to all attacks."