WordNet (r) 3.0 (2006):

squishy
    adj 1: easily squashed; resembling a sponge in having soft
           porous texture and compressibility; "spongy bread" [syn:
           spongy, squashy, squishy, spongelike]

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "squishy":
   baccate, dirty, doughy, flabby, fleshy, macerated, masticated,
   miry, mucky, muddy, mushy, oozy, pasty, pithy, plashy, pulpal,
   pulpar, pulped, pulplike, pulpy, quaggy, slabby, slobby, sloppy,
   sloshy, sloughy, sludgy, slushy, soft, splashy, spongy, sposhy,
   squashy, squelchy, squushy, succulent, turbid, yielding