Tie that’s displaced the first semi, indeed (3,4)
I believe the answer is:
not half
'tie that's displaced the first' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'semi indeed' is the wordplay.
I cannot quite see how this works, but
'semi' could be 'half' ('semi' means 'half') and 'half' is found within the answer.
The remaining letters 'not' 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).
Can you help me to learn more?
(Other definitions for not half that I've seen before include "Forty nine per cent" , "Very much (but less than 50%)!" , "Very much, greatly" , "I warmly agree!" , "Very much (colloq.)" .)