The Collaborative International Dictionary of English v.0.48:

Pooped \Pooped\, p. p. & a. (Naut.)
   (a) Having a poop; furnished with a poop.
   (b) Struck on the poop. [1913 Webster] pooped out

The Collaborative International Dictionary of English v.0.48:

Pooped \Pooped\, Pooped out \Pooped out\, a.
   Tired; exhausted; fatigued. [PJC]

The Collaborative International Dictionary of English v.0.48:

Poop \Poop\, v. i. [imp. & p. p. Pooped; p. pr. & vb. n.
   Pooping.] [Cf. D. poepen. See Pop.]
   To make a noise; to pop; also, to break wind.
   [1913 Webster]