'unevenly-applied' originates from modern English, combining the adverb 'unevenly' (from adjective 'uneven' + suffix '-ly') and 'applied' (the past participle of 'apply').

'uneven' comes from Middle English (formed with prefix 'un-' + 'even'), while 'apply' comes via Old French 'appliquer' from Latin 'applicare'; the compound phrase arose in modern English by combining these elements to describe how something was applied.

Originally 'apply' (from Latin) carried senses like 'to attach' or 'to bring into contact'; over time it broadened to include 'to put on, to use, or to implement', so 'unevenly-applied' evolved to mean 'not put on or implemented evenly' rather than only 'physically attached unevenly'.