Position of diver fixed, beginning to spring off (4)
I believe the answer is:
tuck
'spring off' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's a link between them I don't understand?
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for tuck that I've seen before include "Cosmetic procedure" , "Fold - grub" , "Friar of Sherwood" , "Fold into small space" , "legendary friar" .)