The same entry is taken over by ps.-Zonaras. The meaning given in their gloss, however, is not attested in the few surviving independent occurrences of the transmitted headword verb e)kph/gnusqai (predominantly in Theophrastus, in reference to plants); almost certainly this is a mistake on the part of the Suda or its immediate source(s).
In any event the headword infinitive should be e)kplh/gnusqai (sic), as Theodoridis on Photius, Lexicon epsilon472 has latterly declared. A variant of the verb used in the gloss, e)kplh/ttesqai (cf. LSJ s.v.), it occurs in Thucydides 4.125.1 (on panic striking a Macedonian army in 423 BCE: web address 1); and, probably on the basis of scholia to that passage, earlier lexicography (Moeris, citing 'Thucydides'; Hesychius epsilon1629) had presented entries very similar to this one, apart from the ekpl- headword. (Adler does cite a scholium to Thucydides 4.125.1 as an original source, but Hude's edition of the scholia to Thucydides gives merely 'note e)kplh/gnusqai'.) Post-Suda -- in the C13/14 -- Thomas Magister, Ecloga nominum et verborum Atticorum epsilon151.8-10, sets out the matter most fully of all: "e)plh/gnusqai occurs only in Thucydides: '[sudden fear], as is apt to strike large armies, unaccountably, with astonishment'. You, though, say e)plh/ttesqai."