Okay, get your mind out of the gutter -- it's used of a tree or bush, okay? When it seeds, are they in the form of nuts, as opposed to berries, fruit, cones (as in coniferous), or whatnot. It's a very learned word, and rare, and probably not even used by botanists (but if there are any botanists here who can say otherwise, please speak up). Coined from Latin roots nux (plural nucis), nut + -ferous, bearing.
You pusillanimous, nuciferous, pussy-footer!
(That's what my coworker came up with while trying to guess the meaning -- I think it works just fine.) (ETA: Spelling corrected in example. That's what I get for posting before the coffee kicks in.)