impregnable vs conceptive

impregnable and conceptive both are adjectives.

Word	Noun	Adjective	Verb	Adverb
impregnable	No	Yes	No	No
conceptive	No	Yes	No	No

As adjectives, impregnable and conceptive are synonyms defined as:

impregnable (adjective)	conceptive (adjective)
capable of conceiving	capable of conceiving
immune to attack; incapable of being tampered with
incapable of being overcome, challenged or refuted