'garishly-displayed' is a modern English compound formed from the adverb 'garishly' (itself 'garish' + the adverbial suffix '-ly') and the past participle 'displayed' (from the verb 'display').

'garish' entered English via Middle English (forms like 'garish'/'garrish'), likely influenced by or related to words such as Old French 'garnir' / 'garnish' (to adorn). 'Display' comes into English from Old French (earlier forms like 'despleier' / 'desployer'), ultimately producing the Modern English verb 'display' and its past participle 'displayed'; the compound combining an adverb + participle (e.g., 'garishly displayed') is a straightforward Modern English formation.

Individually, 'garish' developed the sense 'excessively showy or tasteless' while 'display' kept the sense 'to show'; together the compound now specifically means 'shown in a tastelessly showy way.'