肉眼

[ noun ]
the eye unaided by any optical instrument that alters the power of vision or alters the apparent size or distance of objects
<noun.body>
it is not safe to look directly at the sun with the naked eye

Naked \Na"ked\ (n[=a]"k[e^]d), a. [AS. nacod; akin to D. naakt,
G. nackt, OHG. nacchot, nahhot, Icel. n["o]kvi[eth]r, nakinn,
Sw. naken, Dan. n["o]gen, Goth. naqa[thorn]s, Lith. n[*u]gas,
Russ. nagii, L. nudus, Skr. nagna. [root]266. Cf. {Nude}.]
1. Having no clothes on; uncovered; nude; bare; as, a naked
body; a naked limb; a naked sword.

2. Having no means of defense or protection; open; unarmed;
defenseless; as, naked to invasion.

Had I but served my God with half the zeal
I served my king, he would not in mine age
Have left me naked to mine enemies. --King Henry
VIII., Act
iii. sc. 2
(Shakespeare)
[PJC]

Thy power is full naked. --Chaucer.

Behold my bosom naked to your swords. --Addison.

3. Unprovided with needful or desirable accessories, means of
sustenance, etc.; destitute; unaided; bare.

Patriots who had exposed themselves for the public,
and whom they saw now left naked. --Milton.

4. Without addition, exaggeration, or excuses; not concealed
or disguised; open to view; manifest; plain.

The truth appears so naked on my side, That any
purblind eye may find it out. --Shak.

All things are naked and opened unto the eyes of him
with whom we have to do. --Heb. iv. 13.

5. Mere; simple; plain; as, the naked truth.

The very naked name of love. --Shak.

6. (Bot.) Without pubescence; as, a naked leaf or stem; bare,
or not covered by the customary parts, as a flower without
a perianth, a stem without leaves, seeds without a
pericarp, buds without bud scales.

7. (Mus.) Not having the full complement of tones; -- said of
a chord of only two tones, which requires a third tone to
be sounded with them to make the combination pleasing to
the ear; as, a naked fourth or fifth.

{Naked bed}, a bed the occupant of which is naked, no night
linen being worn in ancient times. --Shak.

{Naked eye}, the eye alone, unaided by eyeglasses, or by
telescope, microscope, or other magnifying device.

{Naked-eyed medusa}. (Zo["o]l.) See {Hydromedusa}.

{Naked flooring} (Carp.), the timberwork which supports a
floor. --Gwilt.

{Naked mollusk} (Zo["o]l.), a nudibranch.

{Naked wood} (Bot.), a large rhamnaceous tree ({Colibrina
reclinata}) of Southern Florida and the West Indies,
having a hard and heavy heartwood, which takes a fine
polish. --C. S. Sargent.

Syn: Nude; bare; denuded; uncovered; unclothed; exposed;
unarmed; plain; defenseless.