Throw son into Jaguar, for example (4)
I believe the answer is:
'throw' is the definition.
(I know that throw can be written as cast)
'son into jaguar for example' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'into' is an insertion indicator.
'jaguar for example' becomes 'cat' (jaguar is a kind of cat).
's' put inside 'cat' is 'CAST'.
(Other definitions for cast that I've seen before include "Mould; actors in a play" , "Discard; mould" , "Pot" , "'Ne'er .... a clout till May be out'" , "Troupe" .)