Not prepared to survive, being tiny (4-6)
I believe the answer is:
last-minute
'not prepared' is the definition.
(I've seen this before)
'survive being tiny' is the wordplay.
'survive' becomes 'last' (synonyms).
'being tiny' becomes 'minute' (minute can mean small).
'last'+'minute'='LAST-MINUTE'
'to' is the link.
(Other definitions for last-minute that I've seen before include "Eleventh hour" , "Eleventh-hour" , "Done at the final moment" , "Done at the latest possible moment" , "very late" .)