The Collaborative International Dictionary of English v.0.48:

Savvy \Sav"vy\, Savvey \Sav"vey\, v. t. & i. [Written also
   savey.] [Sp. saber to know, sabe usted do you know?]
   To understand; to comprehend; know. [Slang, U. S.]
   [Webster 1913 Suppl.] Savvy