From fūrtum (“theft”) +‎ -īvus.

• (Classical Latin) IPA^(key): [fuːrˈtiː.wʊs]
• (modern Italianate Ecclesiastical) IPA^(key): [furˈtiː.vus]

fūrtīvus (feminine fūrtīva, neuter fūrtīvum, not comparable, adverb fūrtīvē); first/second-declension adjective

1. stolen
2. secret; furtive, clandestine
   • 29 BCE – 19 BCE, Vergilius, Aeneis 4.171:

     nec iam fūrtīvum Dīdō meditātur amōrem

     no longer does Dido intend a secret love affair

3. hidden, concealed

First/second-declension adjective.

• Catalan: furtiu
• Italian: furtivo
• → Middle French: furtif
  • French: furtif
    • → Dutch: furtief
    • → Romanian: furtiv
  • → Middle English: *furtyve
    • English: furtive
• → Portuguese: furtivo
• → Sicilian: furtivu
• → Spanish: furtivo

• “furtivus”, in Charlton T. Lewis and Charles Short (1879), A Latin Dictionary, Oxford: Clarendon Press
• “furtivus”, in Charlton T. Lewis (1891), An Elementary Latin Dictionary, New York: Harper & Brothers
• “furtivus”, in Gaffiot, Félix (1934), Dictionnaire illustré latin-français, Hachette.