Possibly adapted into Pre-Latin in the form *θūko- or *θīko- and likely related to Ancient Greek σῦκον (sûkon) and Old Armenian թուզ (tʻuz) through a Mediterranean substrate form *tʲuk- or the like.
One possibility is a Semitic loanword. Compare Phoenician 𐤐𐤀𐤂 (pʾg, “half-ripe fig”), Hebrew פַּג (paḡ), פַּגָּה (paggâ, “unripe fig”), Classical Syriac ܦܵܓܵܐ (“unripe fig”).