-tropin

Etymology tree
Proto-Indo-European *trep-der.
Ancient Greek τρέπω (trépō)
Ancient Greek -ᾱ (-ā)
Ancient Greek -η (-ē)
Ancient Greek τροπή (tropḗ)
Proto-Indo-European *-kos
Ancient Greek -κός (-kós)
Ancient Greek -ῐκός (-ĭkós)
Ancient Greek τροπῐκός (tropĭkós)bor.
English -tropic
Proto-Indo-European *-nós
Proto-Indo-European *-iHnos
Proto-Italic *-īnos
Latin -īnusder.
Old French -inbor.
Middle English -in
English -ineclip.
English -in
English -tropin
From -tropic (“attracted to or acting upon”) + -in.