I have seen the definitions of caprificus (caper + ficus = goat + fig) include both pride and fig trees /goat-figs. Are goats considered particularly prideful? I would think they would be more associated with gluttony than any of the other sins.
In its original sense, capri-fīcus just means "wild fig-tree". Its fruits are harder to eat and less pleasant than the domesticated fig-tree (fīcus), but goats can eat them just fine, so the Romans named it the "goat-fig".
However, one thing the caprifīcus was known for was its tenacity: it had a reputation for pushing its roots up underneath the pavement and ruining it. See Persius's Satires 1.25-6:
quo didicisse, nisi hoc fermentum et quae semel intus innata est rupto iecore exierit caprificus?
What's the point of having learned, if not to let this roiling passion, this caprifīcus inside me, tear its way out of my liver all at once?
I've never seen caprifīcus defined as "pride", but I'd guess it comes from this metaphorical usage: it's a tree that doesn't know its place, that strikes back against man-made walls and structures confining it and will happily tear down a house in order to keep growing where it likes.