Jer. 10:8 KJV (With Strong’s)

But they are ζaltogether
'echad (Hebrew #259)
properly, united, i.e. one; or (as an ordinal) first
KJV usage: a, alike, alone, altogether, and, any(-thing), apiece, a certain, (dai-)ly, each (one), + eleven, every, few, first, + highway, a man, once, one, only, other, some, together,
Pronounce: ekh-awd'
Origin: a numeral from 258
ba`ar (Hebrew #1197)
to kindle, i.e. consume (by fire or by eating); also (as denominative from 1198) to be(-come) brutish
KJV usage: be brutish, bring (put, take) away, burn, (cause to) eat (up), feed, heat, kindle, set ((on fire)), waste.
Pronounce: baw-ar'
Origin: a primitive root
and foolish
kacal (Hebrew #3688)
properly, to be fat, i.e. (figuratively) silly
KJV usage: be foolish.
Pronounce: kaw-sal'
Origin: a primitive root
: the stock
`ets (Hebrew #6086)
a tree (from its firmness); hence, wood (plural sticks)
KJV usage: + carpenter, gallows, helve, + pine, plank, staff, stalk, stick, stock, timber, tree, wood.
Pronounce: ates
Origin: from 6095
is a doctrine
muwcar (Hebrew #4148)
properly, chastisement; figuratively, reproof, warning or instruction; also restraint
KJV usage: bond, chastening ((-eth)), chastisement, check, correction, discipline, doctrine, instruction, rebuke.
Pronounce: moo-sawr'
Origin: from 3256
of vanities
hebel (Hebrew #1892)
from 1891; emptiness or vanity; figuratively, something transitory and unsatisfactory; often used as an adverb
KJV usage: X altogether, vain, vanity.
Pronounce: heh'bel
Origin: or (rarely in the abs.) habel {hab-ale'}

Cross References

Heb. in one, or at once.
Jer. 10:14• 14Every man is brutish in his knowledge: every founder is confounded by the graven image: for his molten image is falsehood, and there is no breath in them. (Jer. 10:14)
Jer. 51:17‑18• 17Every man is brutish by his knowledge; every founder is confounded by the graven image: for his molten image is falsehood, and there is no breath in them.
18They are vanity, the work of errors: in the time of their visitation they shall perish.
(Jer. 51:17‑18)
Psa. 115:8• 8They that make them are like unto them; so is every one that trusteth in them. (Psa. 115:8)
Psa. 135:18• 18They that make them are like unto them: so is every one that trusteth in them. (Psa. 135:18)
Isa. 41:29• 29Behold, they are all vanity; their works are nothing: their molten images are wind and confusion. (Isa. 41:29)
Hab. 2:18• 18What profiteth the graven image that the maker thereof hath graven it; the molten image, and a teacher of lies, that the maker of his work trusteth therein, to make dumb idols? (Hab. 2:18)
Zech. 10:2• 2For the idols have spoken vanity, and the diviners have seen a lie, and have told false dreams; they comfort in vain: therefore they went their way as a flock, they were troubled, because there was no shepherd. (Zech. 10:2)
Rom. 1:21‑22• 21Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.
22Professing themselves to be wise, they became fools,
(Rom. 1:21‑22)
the stock.

J. N. Darby Translation

But they are one and all senseless and foolish; the teaching of vanities is a stocke.

JND Translation Notes

Or "wood is an instruction of vanity."