Fasteners in extremes of eloquence but in a loss of splendour (7)
I believe the answer is:
eclipse
'in a loss of splendour' is the definition.
I can't tell whether this defines the answer.
'fasteners in extremes of eloquence' is the wordplay.
'fasteners' becomes 'clips' (clip is a kind of fastener).
'in' indicates putting letters inside.
'extremes of' says to hollow out the word (remove centre letters) (only the letters at the extremes of the word).
'eloquence' with its middle taken out is 'ee'.
'clips' put into 'ee' is 'ECLIPSE'.
'but' is the link.
Can you help me to learn more?
(Other definitions for eclipse that I've seen before include "Darkening of the sun" , "period of darkness" , "concealment" , "Dominate - put in the shade" , "Momentary disappearance of heavenly body" .)