'frequently-kept' is a compound word formed from 'frequently' and 'kept'. 'Frequently' originates from Latin 'frequentia', meaning 'crowded' or 'numerous', and 'kept' is the past participle of 'keep', which comes from Old English 'cēpan', meaning 'to seize' or 'to hold'.

'Frequently' evolved from Latin 'frequentia' through Old French 'frequent' and Middle English 'frequent', while 'kept' evolved from Old English 'cēpan'.

Initially, 'frequently' meant 'crowded' or 'numerous', but evolved to mean 'often', while 'kept' retained its meaning of 'maintained'.