Dative case feminine of a derivative of pous (as adverb); foot-wise, i.e. By walking -- a- (on) foot.
see GREEK pous
STRONGS NT 3979: πεζόςπεζός, πεζῇ πεζον (πέζα; see πέδη), from Homer down;
1. on foot (as opposed to riding).
2. by land (as opposed to going by sea): ἠκολούθησαν πεζοί, Matthew 14:13, T L marginal reading WH marginal reading (so the Sinaiticus manuscript also) for R G πεζῇ (cf. Winers Grammar, § 54, 2; Buttmann, § 123, 9). (The Sept. for רַגְלִי and בְּרֶגֶל.)