Multipurpose tool set in possession of promising person (8)
I believe the answer is:
computer
'multipurpose tool' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'set in possession of promising person' is the wordplay.
'set' becomes 'put' ('put' can be a synonym of 'set').
'in possession of' is an insertion indicator.
'promising person' becomes 'comer' (comer is a kind of person. I am not sure about the 'promising' bit.**).
'put' put into 'comer' is 'COMPUTER'.
Can you help me to learn more?
(Other definitions for computer that I've seen before include "Eg, laptop" , "Electronic calculator" , "Electronic information machine" , "Electronic machine, basis of networks" , "Electronic device for processing data" .)