Young lad’s fall, gets external support (9)
I believe the answer is:
stripling
'young lad's' is the definition.
'stripling' can be an answer for 'lad's' (I've seen this before). I'm not certain of the 'young' bit.
'fall gets external support' is the wordplay.
I cannot really see how this works, but
'fall' could be 'trip' (as in tripping over) and 'trip' is found in the answer.
'support' could be 'sling' (sling is a type of support for member (ie an arm)) and 'sling' is found within the remaining letters.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for stripling that I've seen before include "youngster" , "Young 'un" , "Young man" , "Lad" , "Youth" .)