1. noun /spʌndʒ/
a) Any of various marine invertebrates, mostly of the phylum Porifera, that have a porous skeleton often of silica.
b) A piece of porous material used for washing (originally made from the invertebrates, now often made of plastic).
Syn: sea sponge, bath sponge, sponge cake, sponge pudding
2. verb /spʌndʒ/
a) To take advantage of the kindness of others.
He has been sponging off his friends for a month now.
Wikipedia foundation.