mucchi (heaps, Italian)
Macchi (you stain, Italian)
macci (fools, Latin)
Lacci (laces, Italian)
flacci (flabby / flaccid, pl., Latin)
Facci (do us, Italian)
acci (summon [him], Latin)
As acci mortem, though, it becomes “k*ll yourself” (not gonna try to slip that past automod).
acció
actio (action, Latin)
action (action, English)
actions
Factions
fractions
Jlt had termite
@andersonie has corrected me already 
Frictions
Sorry, hadn’t got that far
fictions
Not sure if friction can have a plural really …
Factions