Say "I am the greatest", forgetting last part? (7)
I believe the answer is:
aliquot
'say i am' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'the greatest forgetting last part?' is the wordplay.
'the greatest' becomes 'ali' (film about Muhammad Ali).
'forgetting' becomes 'quo' (I can't justify this - if you can you should give a lot more credence to this answer).
'last' says to take the final letters.
The last letter of 'part' is 't'.
'ali'+'quo'+'t'='ALIQUOT'
(Other definitions for aliquot that I've seen before include "Equal measure" , "Chemical sample" , "Portion of a larger whole; to quail (anagram)" , "giving exact division" , "Of divisor producing quotient without fraction." .)