Required pointer left out on top of desk (6)
I believe the answer is:
needed
'required' is the definition.
(I know that required can be written as needed)
'pointer left out on top of desk' is the wordplay.
'pointer' becomes 'needle' (as in a needle on a compass).
'left' becomes 'l' (common abbreviation).
'out' indicates named letters should be taken away.
'on top of desk' becomes 'd' (I am not sure about this - if you are sure you should believe this answer much more).
'needle' with 'l' taken away is 'neede'.
'neede'+'d'='NEEDED'
Can you help me to learn more?
(Other definitions for needed that I've seen before include "Missing" , "Was in want of" , "Required; sounds like worked (dough)" , "Required something essential" , "'Wanted, required (6)'" .)