Strong's 421 (ἀνεξιχνίαστος)

---

past finding out; unsearchable

not tracked out, i.e. (by implication) untraceable

---

from G1 (Α) (as a negative particle) and a presumed derivative of a compound of G1537 (ἐκ) and a derivative of G2487 (ἴχνος);