Provide crossing for river or brook (6)
I believe the answer is:
endure
'brook' is the definition.
(I know that brook can be written as endure)
'provide crossing for river' is the wordplay.
'provide crossing' becomes 'end' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'for' means one lot of letters go next to another.
'river' becomes 'Ure' (river in Yorkshire).
'end'+'ure'='ENDURE'
'or' is the link.
Can you help me to learn more?
(Other definitions for endure that I've seen before include "Suffer, tolerate" , "Go through" , "Last (anag.)" , "Bear, suffer" , "Bear, stick it out" .)