It can get screwed into a boot (4)
I believe the answer is:
stud
(Other definitions for stud that I've seen before include "Sex god" , "Animal kept for breeding" , "Place of breeding" , "Small piece of jewellery" , "pin" .)
I believe the answer is:
stud
(Other definitions for stud that I've seen before include "Sex god" , "Animal kept for breeding" , "Place of breeding" , "Small piece of jewellery" , "pin" .)