Foolish person to start mobbing wildly! (5)
I believe the answer is:
limbo
'mobbing wildly' is the definition.
I can't judge whether this defines the answer.
'foolish person to start' is the wordplay.
'foolish' becomes 'lim' (I can't explain this - if you can you should give a lot more credence to this answer).
'person' becomes 'bod' (bod can informally mean a person or body).
'to start' means to remove the last letter (I've seen 'starts' mean this).
'bod' with its last letter removed is 'bo'.
'lim'+'bo'='LIMBO'
Can you help me to learn more?
(Other definitions for limbo that I've seen before include "Dance; uncertain period of waiting" , "Period of indecision" , "dance in West Indies" , "Imaginary place for lost or neglected things" , "Intermediate state; obscurity" .)