I. noun
or per·due ˈpər-(ˌ)dü, -(ˌ)dyü; (ˌ)pər-ˈ
Etymology: French sentinelle perdue, literally, lost sentinel
Date: 1605
obsolete : a soldier assigned to extremely hazardous duty
II. adjective
or per·due per-ˈdue
Etymology: French perdu, masculine, & perdue, feminine, from past participle of perdre to lose, from Latin perdere
Date: 1612
: remaining out of sight