'secretly-kept' originates from the combination of 'secretly' and 'kept', where 'secretly' is derived from the Latin word 'secretus', meaning 'set apart, hidden', and 'kept' is the past participle of 'keep', from Old English 'cepan', meaning 'to seize, hold'.

'secretly-kept' combines the adverb 'secretly' and the past participle 'kept' to form an adjective describing something maintained in secrecy.

Initially, 'secretly' meant 'in a secret manner', and 'kept' meant 'held or retained'. Together, they describe something maintained in secrecy.