Generally, troublesome plants that serve no apparent useful purpose where they grow. While some scholars have endeavored to link with specific plants the various original-language words rendered “weeds” in the Bible, no certain identification is possible.

The Hebrew word boʼ·shahʹ is considered to be derived from a root meaning “stink” and therefore probably embraces a variety of foul-smelling plants, “stinking weeds.” Faithful Job, in effect, stated that if his life course had not been one of integrity, then, instead of barley, let stinking weeds grow.​—Job 31:40.

Another Hebrew term, chohʹach, is understood to designate thorny plants generally, thorny weeds that grow on cultivated ground and quickly take possession of desolated land. (Job 31:40; Isa 34:13; Ho 9:6) The same word appears at Job 41:2, where the allusion seems to be to a thorn put into the gills of a fish for carrying purposes. Chohʹach is also employed in an illustrative sense. (Ca 2:2) A thorny weed in the hand of a drunkard can bring injury to him and to others; so it is with stupid people who use a proverb wrongly because of not understanding it. (Pr 26:9) King Jehoash of  Israel compared the action of proud King Amaziah of Judah in wanting to fight him to a thorny weed’s asking for a marriage alliance with a cedar of Lebanon.​—2Ki 14:8, 9; 2Ch 25:18.

The Hebrew designation shaʹyith appears to denote a variety of weeds that grow on neglected or desolated land. (Isa 5:6; 7:23-25; 27:4) This term, rendered “weeds,” is used figuratively to represent people who by their unfaithfulness have become worthless and fit only for destruction.​—Isa 9:18, 19; 10:17-19; compare Da 4:20-22.

At Proverbs 24:31, the plural form of the Hebrew term qim·mohsʹ, which is commonly rendered “nettle,” appears to denote weeds of all kinds.​—See NETTLE.

The weeds (Gr., zi·zaʹni·a) of Jesus’ illustration at Matthew 13:24-30, 36-43 are generally considered to be bearded darnel (Lolium temulentum), which very much resembles wheat until maturity, when it can be readily distinguished from wheat by its smaller black seeds. This, together with the fact that the roots of these weeds become entwined with the wheat, would make it most inadvisable to pull up the weeds at an early stage. If darnel seeds become mixed with wheat kernels after the harvest, this can have a serious effect upon the eater. Dizziness and even fatal poisoning have been attributed to eating bread containing too much darnel flour. The poisonous properties of darnel seeds are generally believed to stem from a fungus growing within them.