Any of various marine invertebrates, mostly of the phylum Porifera, that have a porous skeleton often of silica.

A piece of porous material used for washing (originally made from the invertebrates, now often made of plastic).

A porous material such as sponges consist of.

To take advantage of the kindness of others.

“He has been sponging off his friends for a month now.”

To get by imposition; to scrounge.

“to sponge a breakfast”

To deprive (somebody) of something by imposition.