Mocking imitation of leaving the ground (7)

'mocking imitation' is the definition.
'takeoff' can be an answer for 'imitation' (takeoff is a kind of imitation). I'm unsure of the 'mocking' bit.

'leaving the ground' is the wordplay.
I cannot really see how this works, but
'leaving' could be 'off' (as in 'I'm off') and 'off' is found in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
The remaining letters 'ake' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

'of' acts as a link.

Can you help me to learn more?