penitus

Etymology 1
From the root of and. De Vaan reconstructs an extended stem as the source of,  and. The adverb appears to be formed as.

Adverb

 * 1) inwardly, inside
 * 2) (from) within
 * 3) thoroughly, (not) at all
 * 4) within, far, far down, far away, deeply
 * 1) thoroughly, (not) at all
 * 2) within, far, far down, far away, deeply
 * 1) within, far, far down, far away, deeply

Adjective

 * 1) inner, inward

Etymology 2
From.

Adjective

 * 1)  having a tail