It's there in case of a fall or a nasty problem with feet (6,3)
I believe the answer is:
safety net
'it's there in case of a fall' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'a nasty problem with feet' is the wordplay.
'problem with' indicates anagramming the letters.
'nasty' with its letters anagrammed with 'feet' gives 'SAFETY-NET'.
'or' is the link.
Can you help me to learn more?
(Other definitions for safety net that I've seen before include "insurance" , "Means of protection" , "This may prevent dangerous mishap" , "It affords protection for those in difficulty" , "precaution" .)