When you see this word – which may not happen often – what do you do about the l in it? You might be inclined to say it, but you ought not to (as with walk and caulk – oh, balk can also be spelled baulk). That l is a ridge that was left between the furrows in the field of this word, but is now to be driven over, disregarded; though it may seem to be a structural beam, or a dividing line, do not recoil at it. Simply disregard it. What I’m saying is: the l in balk may seem a balk, but do not balk at it or let it balk you; simply balk it.
Balk, you see, is an old Germanic word that meant first “dividing ridge” or “bar”; an old meaning is “a ridge left between ploughed furrows.” But it can also refer to a structural beam or similar bar. Or, by extension, the area behind a line on a billiard table.
The noun balk also has meanings that relate to the verb balk, which derives figuratively from the noun balk. To balk can be to stop short or shy away from (not related to the noise chickens make, though it does sound like baaalk balk balk), or to avoid or refuse or let slip, or to ignore, or (in baseball) to make a certain kind of error – or, on the other hand, to put an obstacle in the way or to frustrate. So a balk can be a refusal, just as balking at something is refusing to do it (cue Hall and Oates: “I can’t go for that!”).
That, anyway, is the bulk of the available senses. (Bulk is not related to balk, by the way.) As you can see, this term is not balk and white – I mean black and white. Or perhaps it is, both at the same time… Word taster Allan Jackson, in suggesting this word, has mused on whether it is a contranym (a word that can mean opposite things). I think there’s a case to be made for that: is hesitation a contrary to outright refusal? Perhaps (inactive versus active), or perhaps not (both non-doing); but hindering someone and being hindered are at least obverses of each other. (There is also the matter of Fairuza Balk, whom most lads would not balk at looking at, but that’s a digression.)
You can even see the different senses of the word in its letter forms, if you want: the obstacle b versus the rebound k (consider the upright bar to the the base – or just see the rebound ‹ off the ball‹)… Or is it just the bursting of a bubble, b > k?