Gloomy detachment of soldiers encircles Lima (5)
I believe the answer is:
unlit
'gloomy' is the definition.
Both the answer and definition are adjectives. Maybe there's an association between them I don't understand?
'detachment of soldiers encircles lima' is the wordplay.
'detachment of soldiers' becomes 'unit' (I've seen this before).
'encircles' indicates putting letters inside.
'lima' becomes 'L' (phonetic alphabet: alpha, bravo, charlie etc.).
'unit' going around 'l' is 'UNLIT'.
Can you help me to learn more?
(Other definitions for unlit that I've seen before include "not exactly bright" , "Without illumination" , "not provided with a lamp?" , "Perhaps invisible" , "Left in the dark" .)