That boost kleptomaniacs get when they steal? (4)
I believe the answer is:
lift
'they steal?' is the definition.
'lift' can be an answer for 'steal?' (I've seen this before). I'm not certain of the 'they' bit.
'that boost kleptomaniacs get when' is the wordplay.
'that boost kleptomaniacs' becomes 'lt' (I can't justify this - if you can you should give a lot more credence to this answer).
'get' indicates putting letters inside.
'when' becomes 'if'.
'lt' enclosing 'if' is 'LIFT'.
Can you help me to learn more?
(Other definitions for lift that I've seen before include "Raise the vertical conveyor" , "Exalt" , "Raise - hoist" , "It's an elevator in USA" , "Raise; elevator" .)