Run across flood on the way back (4)
I believe the answer is:
meet
'run across' is the definition.
(synonyms)
'flood on the way back' is the wordplay.
'flood on' becomes 'me' (I can't justify this - if you can you should give a lot more credence to this answer).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'way' becomes 'e' (Compass direction - East).
'back' says the letters should be written in reverse.
't'+'e'='te'
'te' written backwards gives 'et'.
'me'+'et'='MEET'
Can you help me to learn more?
(Other definitions for meet that I've seen before include "Attend" , "See 24" , "Appropriate" , "Bump into" , "Hunting gathering" .)