'infrequently-addressed' is a compound of the adverb 'infrequently' and the past-participial adjective 'addressed'. 'infrequently' is formed from the negative prefix 'in-' + 'frequently' (from Latin 'frequens' meaning 'repeated, numerous'), and 'addressed' comes from the verb 'address' (from Old French 'adresser', ultimately from Latin elements including 'ad-' meaning 'to' and roots related to 'direct').

'infrequent' developed from Latin 'frequens' → Old French/Medieval Latin forms → Middle English 'frequent'; the negative prefix 'in-' and the adverbial suffix '-ly' produced 'infrequently'. 'address' entered English from Old French 'adresser' into Middle English as 'addressen' and its past participle 'addressed' was used to mean 'directed to' or 'dealt with'. In Modern English the two elements combined to form the descriptive compound 'infrequently-addressed'.

Initially, 'infrequent' meant 'not occurring often' (a meaning that has largely remained), while 'address' originally meant 'to direct' and later broadened to mean 'to speak to, deal with, or consider'. The compound therefore now conveys 'rarely dealt with or discussed'.