Crack code's initial change, turning spades into clubs (7)
I believe the answer is:
crevice
'crack' is the definition.
(synonyms)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for crevice that I've seen before include "Narrow crack" , "Cleft, fissure" , "Narrow rock fissure" , "Crack or fissure." , "Opening" .)