来自古法语 sauf,安全的，受保护的，来自拉丁语 salvus,安全的，健康的，完整的，来自 PIE*sol, 完整的，整个的，词源同 solid,save,salvation.字母 l 软化为 u,最终脱落。引申词义保险箱等。
英文词源
safe
safe: [13] Like save, and indeed salvage and salvation, safe comes from Latin salvus ‘uninjured’. It reached English via Old French sauf. Salvus itself went back to a prehistoric Indo-European *solwos ‘whole’, which came from the same base that produced English soldier, solemn, and solid. The noun safe ‘strongbox’ [15] was originally save, a derivative of the verb, but by the late 17th century it had, under the influence of the adjective, become safe.
The plant-name sage [14] comes via Old French sauge from Latin salvia, etymologically the ‘healing’ plant, a derivative of salvus (English acquired salvia itself in the 19th century). => sage, salute, salvage, salvation, salvia, save, soldier, solemn, solid
safe (n.)
"chest for keeping food or valuables," early 15c., save, from Middle French en sauf "in safety," from sauf (see safe (adj.)). Spelling with -f- first recorded 1680s, from influence of safe (adj.).
safe (adj.)
c. 1300, "unscathed, unhurt, uninjured; free from danger or molestation, in safety, secure; saved spiritually, redeemed, not damned;" from Old French sauf "protected, watched-over; assured of salvation," from Latin salvus "uninjured, in good health, safe," related to salus "good health," saluber "healthful," all from PIE *solwos from root *sol- "whole" (cognates: Latin solidus "solid," Sanskrit sarvah "uninjured, intact, whole," Avestan haurva- "uninjured, intact," Old Persian haruva-, Greek holos "whole").
As a quasi-preposition from c. 1300, on model of French and Latin cognates. From late 14c. as "rescued, delivered; protected; left alive, unkilled." Meaning "not exposed to danger" (of places) is attested from late 14c.; of actions, etc., "free from risk," first recorded 1580s. Meaning "sure, reliable, not a danger" is from c. 1600. Sense of "conservative, cautious" is from 1823. Paired alliteratively with sound (adj.) from late 14c. The noun safe-conduct (late 13c.) is from Old French sauf-conduit (13c.).
双语例句
1. Just play it safe, cover your ass, keep your head down.
要谨慎行事，保护好自己并保持低调。
来自柯林斯例句
2. Rock'n'roll has become so commercialised and safe since punk.
摇滚乐自从朋克乐以后就已经过于商业化而缺乏新意了。
来自柯林斯例句
3. I wanted to get her away to somewhere safe.
我想带她逃到一个安全的地方。
来自柯林斯例句
4. In order to make it safe, the element is electrically insulated.
为安全起见，该元件作了电绝缘处理。
来自柯林斯例句
5. The nearest safe anchorage was in Halifax, Nova Scotia.