Failure to meet goal causes Swift to keel over (9)
I believe the answer is:
shortfall
'failure' is the definition.
(thesaurus)
'to keel over' is the wordplay.
'to' becomes 'short' (I can't explain this - if you can you should give a lot more credence to this answer).
'keel over' becomes 'fall' (I've seen this before).
'short'+'fall'='SHORTFALL'
'to meet goal causes swift' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for shortfall that I've seen before include "Deficiency" , "Loss" , "Deficit of something required" , "lack" , "what we're lacking" .)