First two leaving subdued and tense (8)
I believe the answer is:
strained
'first two' is the definition.
Both the definition and answer are adjectives. Maybe you can see a link between them that I don't see?
'subdued and tense' is the wordplay.
'subdued' becomes 'ed' (I am not sure about this - if you are sure you should believe this answer much more).
'and' says to put letters next to each other (I've seen this in other clues).
'tense' becomes 'strain' (synonyms).
'ed' put after 'strain' is 'STRAINED'.
'leaving' is the link.
(Other definitions for strained that I've seen before include "Awkward" , "Under stress or lacking spontaneity" , "Under pressure" , "Forced -- like baby food?" , "Filtered" .)