The two glosses make a distinction between a passive "goad-struck" (i.e. someone deserving torture, like ke/ntrwn, kappa 1344), and an active "goad-striker" (e.g. charioteer); these should be distinguished by accent (kentro/tupos vs. kentrotu/pos, LSJ s.v.), although the distinction is often effaced in Byzantine Greek.
[1] Gloss from Hesychius kappa2234 and Photius kappa571 Theodoridis (with paroxytone lemma). The word also appears in kappa 1344. The Etymologicum Gudianum glosses the similar kentro/tupton as "someone deserving whipping" (mastigi/as). The only literary instance is Libanius, Letters 226.5: "a knavish and goad-struck little man attacked the orator"; the lexicographers' gloss "knavish" could well be from that context. Greek Anthology 9.543 (Philip) uses the similar kentrotuph/s as "goad-struck", referring to colts.
[2] From the scholia on Aristophanes, Clouds 450 (repeated in kappa 1344), glossing ke/ntrwn "rogue, someone tortured with a goad": "insofar as we call charioteers goad-strikers, as they strike horses with goads".