i'm sure there are at least 6 more words,,,,
but.... 'Slipless' doesn't cut the mustard' at this point, as much as i'd like it to.
All I've got to follow "spillers" is:
Aprilless (like a year with 11 months)
Aprilless is nice, but a no go, as you know.
The other words that could have followed lipless were ellipses, ellipsis, pileless, misspell, and slipsole. None of which will help you find the one word that can follow SPILLERS. This will help, though: add an E.
There is at least one word that can follow PERILLESS. (Add a P.)