The Collaborative International Dictionary of English v.0.48:

Squiffy \Squif"fy\ (skw[i^]f"f[y^]), a.
   Somewhat intoxicated; tipsy. [Slang] --Kipling.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

squiffy
    adj 1: very drunk [syn: besotted, blind drunk, blotto,
           crocked, cockeyed, fuddled, loaded, pie-eyed,
           pissed, pixilated, plastered, slopped, sloshed,
           smashed, soaked, soused, sozzled, squiffy,
           stiff, tight, wet]