Close call with nothing to lose (4)
I believe the answer is:
shut
'close' is the definition.
(I know that close can be written as shut)
'call with nothing to lose' is the wordplay.
'call' becomes 'shu' (I can't justify this - if you can you should give a lot more credence to this answer).
'with' means one lot of letters go next to another.
'nothing' becomes 'O' (looks like zero - 0).
'lose' is a deletion indicator.
'to' with 'o' taken out is 't'.
'shu'+'t'='SHUT'
Can you help me to learn more?
(Other definitions for shut that I've seen before include "not accepting visitors" , "See 19" , "Push to" , "Slam" , "Closed" .)