Develop play oddly following cross into goal (6)
I believe the answer is:
expand
'develop' is the definition.
(I know that develop is a kind of expand)
'play oddly following cross into goal' is the wordplay.
'play oddly' becomes 'pa' (I can't justify this - if you can you should give a lot more credence to this answer).
'following' means one lot of letters go next to another.
'cross' becomes 'x' (an X is a cross).
'into' is an insertion indicator.
'goal' becomes 'end' (both can mean a purpose).
'pa' after 'x' is 'xpa'.
'xpa' going into 'end' is 'EXPAND'.
Can you help me to learn more?
(Other definitions for expand that I've seen before include "Become larger or more extensive" , "Walk through water" , "Dilate" , "Amplify" , "Distend" .)