Straw breaking camel's back, doubly profligate (7)
I believe the answer is:
wastrel
'profligate' is the definition.
(I know that wastrel is a type of profligate)
'straw breaking camel's back doubly' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'straw' is 'wastr' which is present in the answer.
The remaining letters 'el' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for wastrel that I've seen before include "Profligate" , "Person who dissipates resources self-indulgently" , "Good-for-nothing person" , "Ne'er-do-well" , "A useless, good for nothing fellow" .)