Elite soldiers behind hotel window frame (4)
I believe the answer is:
sash
'window frame' is the definition.
(I've seen this before)
'elite soldiers behind hotel' is the wordplay.
'elite soldiers' becomes 'sas' (Special Air Service).
'behind' says to put letters next to each other.
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'sas'+'h'='SASH'
(Other definitions for sash that I've seen before include "Band of cloth" , "Framework to hold the panes of a window" , "Broad band, the one me father wore?" , "(Uniform) strip; window-frame" , "Style of window" .)