Wind remained fickle, lacking intensity initially (7)
I believe the answer is:
meander
'wind' is the definition.
(to meander is to wind around)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for meander that I've seen before include "Wind, bend" , "Wandering direction" , "Wander in leisurely way, like stream" , "turning thereon?" , "Wander aimlessly like a stream" .)