proper

• adj.適切な; それ自身の; 特有の; まともな
• adv.完全に
• n. （固有）人名；（英?独）Propper.

古フランス語のpropre「所有する、適切な」から、ラテン語のproprius「所有する」から、ラテン語のpro privo「個人的に所有する」から、privus「個人的な、私的な」から、語源的にはprivateと同じ。

proper

proper: [13] Proper originally meant ‘belonging to itself, particular to itself’ (a sense now defunct in English except in certain fossilized contexts, such as the astronomical term proper motion). It comes via Old French propre from Latin prōprius ‘one’s own’, which may have been a lexicalization of the phrase prō prīvō, literally ‘for the individual’ (prīvus is the source of English private). The word developed widely in meaning in Latin, but its main modern English senses, ‘correct’ and ‘morally right’, are of later evolution. Appropriate [15] goes back to a late Latin derivative.
=> appropriate, property

proper (adj.)

c. 1300, "adapted to some purpose, fit, apt; commendable, excellent" (sometimes ironic), from Old French propre "own, particular; exact, neat, fitting, appropriate" (11c.), from Latin proprius "one's own, particular to itself," from pro privo "for the individual, in particular," from ablative of privus "one's own, individual" (see private (adj.)) + pro "for" (see pro-). Related: Properly.

From early 14c. as "belonging or pertaining to oneself; individual; intrinsic;" from mid-14c. as "pertaining to a person or thing in particular, special, specific; distinctive, characteristic;" also "what is by the rules, correct, appropriate, acceptable." From early 15c. as "separate, distinct; itself." Meaning "socially appropriate, decent, respectable" is first recorded 1704. Proper name "name belonging to or relating to the person or thing in question," is from late 13c., a sense also preserved in astronomical proper motion (c. 1300). Proper noun is from c. 1500.

1. He denied that he 'd failed to keep a proper lookout that night.

彼はその夜の見張りが弱いことを否定した。

2.Catherine demonstrated the proper way to cleanse the face.

キャサリンは洗顔の正しい方法を示した。

3.Britain imposed fines on airlines which bring in passengers without proper papers.

イギリスでは、キャリア証明書が不揃いな乗客が国内に進出した航空会社に罰金を科す。

4.We tend to imagine that the Victorians were very prim and proper .

ビクトリア時代の人を非常に古風で、規則正しいと想像する傾向がある。

5.Carol managed a few proper snivels for the sake of appearance.

格好をするために、キャロルは適時に鼻を何度か吸った。