reconnoiter v.

early 15c., recognisen, "resume possession of land," a back-formation from recognizance, or else from Old French reconoiss-, present-participle stem of reconoistre "to know again, identify, recognize," from Latin recognoscere "acknowledge, recall to mind, know again; examine; certify," from re- "again" (see re-) + cognoscere "to get to know, recognize" (see cognizance).

With ending assimilated to verbs in -ise, -ize. The meaning "know (the object) again, recall or recover the knowledge of, perceive an identity with something formerly known or felt" is recorded from 1530s. Related: Recognized; recognizing.

*gnō-, Proto-Indo-European root meaning "to know."

It forms all or part of: acknowledge; acquaint; agnostic; anagnorisis; astrognosy; can (v.1) "have power to, be able;" cognition; cognizance; con (n.2) "study;" connoisseur; could; couth; cunning; diagnosis; ennoble; gnome; (n.2) "short, pithy statement of general truth;" gnomic; gnomon; gnosis; gnostic; Gnostic; ignoble; ignorant; ignore; incognito; ken (n.1) "cognizance, intellectual view;" kenning; kith; know; knowledge; narrate; narration; nobility; noble; notice; notify; notion; notorious; physiognomy; prognosis; quaint; recognize; reconnaissance; reconnoiter; uncouth; Zend.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit jna- "know;" Avestan zainti- "knowledge," Old Persian xšnasatiy "he shall know;" Old Church Slavonic znati "recognizes," Russian znat "to know;" Latin gnoscere "get to know," nobilis "known, famous, noble;" Greek gignōskein "to know," gnōtos "known," gnōsis "knowledge, inquiry;" Old Irish gnath "known;" German kennen "to know," Gothic kannjan "to make known."

military slang shortening; 1918 for reconnaissance (n.); 1966 for reconnoiter (v.).