Definition from Wiktionary, the free dictionary
British slang, from 1923, combining (like a popular etymology) two meanings of stark (“strong, utterly; barren”) with stark naked, which is from Old English steort (“tail”), referring to the tail-end (as in butt-naked).
- (RP) IPA: /ˈstɑːkəz/, X-SAMPA: /"stA:k@z/
- (US) enPR: stärʹkərz, IPA: /ˈstɑrkɚz/, X-SAMPA: /"stArk@`z/
starkers (not comparable)
- (chiefly UK, slang) Completely nude.
- Entering the bathroom, I found Bill there, still starkers after his bath.
- in one's birthday suit
- in the bare
- in the nuddy
- in the nude
- naked as the day one was born
Related terms 
- “starkers” in Douglas Harper, Online Etymology Dictionary (2001).