συνηλικιώτηςsynēlikiṓtēs

one of the same age, an equal in age: Galatians 1:14.

Greek (New Testament) · G4915

Same root

σύνsýn · G4862with or together (but much closer than G3326 (μετά) or G3844 (παρά)), i.e. by association, companionship, process, resemblance, possession, instrumentality, addition, etc.
ἡλικίαhēlikía · G2244maturity (in years or size)

Where it appears

Appears 1 times in the Bible.

Galatians 1:14 I was far ahead of my fellow Jews in my zeal for the traditions of my ancestors.

Source: G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922), public domain.