Once a Srivaishnava asked Bhattar "Who is a mumukshu (one who seeks liberation)?"

Bhattar replied "One who considers the unseen as the seen and the seen as the unseen is a mumukshu".

That is, a mumukshu is one who, due to faith in acharyas, considers His eternal abode and the service there which are not visible in this world, as seen. And, discards all things of this world, which are visible to the eyes, as non-existent.