Picture a ploughed field. Between the cut strips there is a low ridge of earth where the blade never went. That ridge is a balk: one long solid thing lying across the ground, in the way. The same word was used for the heavy beam laid across a house from wall to wall, which is the same shape moved indoors. You can think of everything else as growing out of that one picture. If something lies across your path, you stop when you reach it, so a person balks at a price and a horse balks at a fence. If you lay something across another person's path, you balk them. And a pitcher's motion can stop half way, as though it had hit a ridge.
Wiktionary records balk as coming from Middle English balke, from Old English balca, either from or influenced by Old Norse balkr, meaning a partition or a ridge of land, and notes the cognates Dutch balk and German Balken, both meaning beam. The ridge and the beam are therefore the oldest layer, not a later metaphor.
來源記載：balk 來自中古英語 balke、古英語 balca，並來自或受古北歐語 bálkr（隔間、土埂）影響；同源詞有荷蘭文 balk、德文 Balken，都是「樑」。也就是說，「土埂」和「橫樑」是這個字最早的一層，不是後來才加上的比喻。
Wiktionary (kaikki extract in this packet), balk etymology 1, source_ref kaikki:3f6f69a190036ae4:612624003
Three branches
走到那裡就停住：人與動物不肯往前
路上有東西橫著，走到那裡自然就停。這一家把核心畫面裡「擋著」的部分，換成人心裡的那道埂。
verb · C1
To stop and refuse to do something, or to clearly show that you do not want to do it, because it seems too hard, too expensive, or too unpleasant. It is usually used with 'at': balk at something, balk at doing something.
卻步／不肯做
動作做到一半卡住：球場上的假動作
這一家把「碰到埂就停」搬到一個動作內部：動作自己衝到一半就中斷了。
verb · C2
In baseball, if a pitcher balks, they begin the motion of throwing the ball and then stop, or make a fake move meant to fool a runner. It is against the rules. This use is American English.
（棒球）投手犯規停頓
把埂搬到別人前面：擋下對方
前面幾家是自己碰到埂；這一家是你（或天氣、規定）就是那道埂，橫在別人路上。
verb · C2
To stop someone from getting or doing what they want, or to stop a plan from going ahead. The source marks this use as formal, and it takes an object: balk somebody, balk something. It is often used in the passive: be balked.
阻撓、擋下
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
Balkname
A surname.
balknoun詞源 1/bɔːk/
agriculturebusinesslifestyleAn uncultivated ridge formed in the open field system, caused by the action of ploughing.
archaeologyhistoryhuman-sciencesThe wall of earth at the edge of an excavation.
Beam, crossbeam; squared timber; a tie beam of a house, stretching from wall to wall, especially when laid so as to form a loft, "the balks".
A hindrance or disappointment; a check.
A sudden and obstinate stop.
obsoleteAn omission.
ball-gamesbaseballgamesA deceptive motion.
hobbieslifestylesportsA deceptive motion.
ball-gamesbilliardsgamesThe area of the table lying behind the line from which the cue ball is initially shot, and from which a ball in hand must be played.
ball-gamesgameshobbiesThe area of the table lying behind the baulk line.
fishinghobbieslifestyleThe rope by which fishing nets are fastened together.
balkverb詞源 1/bɔːk/
To be unwilling to do something; to refuse to proceed or do or allow something, either in general or only temporarily.
To stop short and refuse to go on or do something (such as jump).
To move fitfully, stopping frequently.
To leave or make a balk or balks (ridges) in; to leave a ridge in by leaving partly unploughed.
To stop, check, block (by or as if by an obstacle); to hinder, impede, thwart.
obsoleteTo leave heaped up; to heap up in piles.
obsoleteTo pass over or by (either by chance or intentionally); to avoid in passing.
obsoleteTo pass over or by (either by chance or intentionally); to avoid in passing.
obsoleteTo pass over or by (either by chance or intentionally); to avoid in passing.
obsoleteTo refuse or fail to use (something), either through error or intentionally.
obsoleteTo refuse or fail to use (something), either through error or intentionally.
To disappoint, frustrate, or check.
obsoleteTo quibble or bandy words with; engage in opposing, contradicting, or arguing with.
hobbieslifestylesportsTo make a balk, a deceptive motion to deceive another player.
balknoun詞源 2/bɔːk/
dialectalA small brass ornament fixed at the top of a wand.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。