Papa and Nana's cycling collision (5)
I believe the answer is:
prang
'collision' is the definition.
(I've seen this before)
'papa and nana's cycling' is the wordplay.
'papa' becomes 'P' (phonetic alphabet: alpha, bravo, charlie etc.).
'and' means one lot of letters go next to another.
'nana's cycling' becomes 'rang' (I am not sure about this - if you are sure you should believe this answer much more).
'p'+'rang'='PRANG'
Can you help me to learn more?
(Other definitions for prang that I've seen before include "Crash (informal)" , "Minor shunt" , "Plane or car crash" , "Crash (a car, aircraft) (colloq.)" , "Crash (a motor vehicle)" .)