impenetrable

Involved is a related term of impenetrable.

As adjectives the difference between involved and impenetrable

is that involved is complicated while impenetrable is impenetrable.

As a verb involved

is (involve).

Impenetrable is a related term of mystifying.

As adjectives the difference between impenetrable and mystifying

is that impenetrable is impenetrable while mystifying is unusual.

As a verb mystifying is

.

As adjectives the difference between arduous and impenetrable

is that arduous is needing or using up much energy; testing powers of endurance while impenetrable is not penetrable.

Wearisome is a related term of impenetrable.

As adjectives the difference between wearisome and impenetrable

is that wearisome is tiresome, tedious or causing fatigue while impenetrable is impenetrable.

Unfathomable is a related term of impenetrable.

As adjectives the difference between unfathomable and impenetrable

is that unfathomable is impossible to fathom or understand; incomprehensible while impenetrable is impenetrable.

Secret is a related term of impenetrable.

As adjectives the difference between secret and impenetrable

is that secret is being or kept hidden while impenetrable is impenetrable.

As a noun secret

is (countable|uncountable) knowledge that is hidden and intended to be kept hidden.

As a verb secret

is to make or keep secret.

Hidden is a related term of impenetrable.

As adjectives the difference between hidden and impenetrable

is that hidden is that has been moved out of sight invisible or unapparent while impenetrable is impenetrable.

As a verb hidden

is .

Laborious is a related term of impenetrable.

As adjectives the difference between laborious and impenetrable

is that laborious is requiring much physical effort; toilsome while impenetrable is impenetrable.

Intricate is a related term of impenetrable.

As adjectives the difference between intricate and impenetrable

is that intricate is having a great deal of fine detail or complexity while impenetrable is impenetrable.

As a verb intricate

is to become enmeshed or entangled.

Cryptic is a related term of impenetrable.

As adjectives the difference between cryptic and impenetrable

is that cryptic is having hidden meaning while impenetrable is impenetrable.

As a noun cryptic

is (informal) a cryptic crossword.