Low-down beam, large only at one end (5)
I believe the answer is:
intel
'low-down' is the definition.
(low-down can mean information or intelligence)
'beam large only at one end' is the wordplay.
I cannot quite see how this works, but
'large' could be 'l' (eg in clothes sizes) and 'l' is located in the answer.
'at' could be 'in' and 'in' is located in the answer.
The remaining letters 'te' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
(Other definitions for intel that I've seen before include "US chip manufacturer" , "Information" , "silicon chip manufacturer" , "military info" , "Chip manufacturer based in California" .)