apaccakkha : [adj.] unseen; not realised; not tested.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]

Apaccakkha (adj.) [a + paṭi + akkha] unseen; in instr. f. apaccakkhāya as adv. without being seen, not by direct evidence Miln 46 sq.

Pali-English Dictionary, TW Rhys Davids, William Stede,