'balk' originates from Old English 'balca' and Old Norse 'balkr', where the root meant 'beam' or 'ridge' (a structural timber or natural barrier).

'balk' changed from Middle English forms such as 'balke'/'balk', originally referring to a beam or ridge, and by metaphor extended to mean an obstacle; from this sense developed the verbal meaning 'to stop short or refuse to proceed', leading to derived forms like 'balkingly'.

Initially it meant 'beam' or 'ridge' (a physical obstacle), but over time it evolved into the figurative sense 'to hesitate or refuse to proceed', which underlies 'balkingly' meaning 'in a hesitant or unwilling manner'.