'spidery' is formed in English from the noun 'spider' + the adjective-forming suffix '-y' (meaning 'characterized by' or 'having the quality of').

'spider' comes from Middle English forms such as 'spidder' or 'spydere', which derive from Old English (earlier) forms related to Proto-Germanic roots meaning 'spinner'; the adjective 'spidery' arose later in English by adding '-y' to 'spider'.

Originally referring to the animal 'spider,' the word's derivative 'spidery' came to mean 'resembling a spider' and was later extended metaphorically to describe thin, delicate, or long-limbed shapes and certain styles of handwriting or line work.