Musical instruments to entertain elderly in low spirits (8)
I believe the answer is:
doldrums
'low spirits' is the definition.
(I've seen this before)
'musical instruments to entertain elderly' is the wordplay.
'musical instruments' becomes 'drums' (drum is a kind of musical instrument).
'to entertain' means one lot of letters goes inside another.
'elderly' becomes 'old' (similar in meaning).
'drums' going around 'old' is 'DOLDRUMS'.
'in' acts as a link.
(Other definitions for doldrums that I've seen before include "Area of calms between the northern and southern trade winds of the Atlantic and Pacific" , "Depressed state of mind" , "Belt of light winds near the equator" , "Belt of calm where winds from north and south come together" , "equatorial area" .)