Form a theory about unusual step in a clue? (9)
I believe the answer is:
speculate
'form' is the definition.
Although both the answer and definition are verbs in their base form, I don't understand how they can define each other.
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for speculate that I've seen before include "Gamble on investments" , "Buy in hope of profit, but with risk of loss" , "Play the market" , "Form opinion without definite knowledge" , "Bet; theorise" .)