E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Fool’s Bolt.
A fool’s bolt is soon shot (Henry V., iii. 7). Simpletons cannot wait for the fit and proper time, but waste their resources in random endeavours; a fool and his money are soon parted. The allusion is to the British bowmen in battle; the good soldier shot with a purpose, but the foolish soldier at random. (See Prov. xxix. 11.)
