The headword (instanced in the final quotation given) is a contracted, epic, present active infinitive; see generally LSJ s.v. perispa/w (I draw off from around, strip off).
[1] The first glossing infinitive, from the verb e)capata/w (I deceive utterly), is the same form as the headword. The headword is identically glossed in Photius, Lexicon pi758 Theodoridis.
[2] From a scholion (= scholia vetera) to Sophocles, Electra 732 (web address 1; cf. delta 331), where the Athenian charioteer pulls back from a huge crash involving the racers (all except for Orestes, who was riding last at that moment); Jahn, p. 37. [In her critical apparatus Adler notes that Aemilius Portus pointed out that Sophocles reads *paraspa=| (he draws forcibly aside), even though the Suda repeats the present headword in the quoted line at delta 331; also that ms F transmits perispa=tai, he removes himself outside.]
[3] Polybius 1.26.1 (web address 2), on the Roman strategy in 256 BCE prior to the Battle of Ecnomus (Eknomos, Barrington Atlas Map 47 grid D4), a hill near the town of Phintias (present-day Licata, Italy), on Sicily's southern coast, during the First Punic War (264-241); Walbank, pp. 84-7. [Adler reports that ms V omitted pro/qesis (purpose, plan).]