Let down (12)
'let down' is the definition.
(I know that let down can be written as lower)
This is the entire clue.
(Other definitions for lower that I've seen before include "Less high in place or position" , "Farther down" , "Move something down" , "where are trousers in relation?" , "Depress" .)
'let down' is the definition.
(to let someone down is to disappoint them)
This is all the clue.
(Other definitions for disappointed that I've seen before include "Sad and let-down" , "Let-down, frustrated" , "Let down" , "Saddened" , "Unhappy" .)