while we are in this tent

Paul speaks of the physical body as if it were a "tent."

in this tent, we groan

The word "tent" refers to "the earthly dwelling that we live in."

Paul refers to the difficulties that the physical body experiences as if they were heavy objects that are difficult to carry.

Here "to be unclothed" refers to the death of the physical body; "to be clothed" refers to the resurrection body that God will give.

"to be without clothes" or "to be naked"

The physical body that will die will be replaced by a resurrection body that will live forever.

"so that life may swallow up what is mortal"