fac

The most literal member: Latin *manus* (hand) + factum (made) = 'made by hand.' Ironically the word now means the opposite — large-scale machine production in factories. The hand vanished, the 'making' stayed. It also reveals *fac* in its purest, undisguised form, right after the *u*.

*ef-* (a form of ex-, 'out') + fect (done) = 'what has been done out' — i.e. the result that something produces. This is why *effect* is an outcome and *affect* (to *do toward*) is the action upon something. The same fect core spawns *effective* (producing the result) and *efficient* (producing it without waste).

*ef-* (out) + fic (a weakened *fac*) + -ient = 'doing the work out to full effect.' Vowel weakening is on full display: *facere*'s *a* becomes *i*. Efficient means the doing produces maximum result for minimum input — the result gets *made* with no waste.

*satis* (enough) + -fy (from -ficāre, 'to make') = 'to make enough.' To satisfy someone is literally to *make* things *enough* for them. The noun **satisfaction** keeps the older *fac* spelling, showing the -fy / -faction pair that runs through this family (clarify/clarification, etc.).

*per-* (thoroughly, all the way through) + fect (done) = 'thoroughly done,' with nothing left to do. That is why a perfect job needs no fixing — it has been completed to the last detail. Note the stress shift: PER-fect (adj.) vs per-FECT (verb, 'to make perfect').