Large sighs heard following umpire’s decision (7)
I believe the answer is:
outsize
'large' is the definition.
(similar in meaning)
'sighs heard following umpire's decision' is the wordplay.
'heard' shows a homophone (sound like).
'following' says to put letters next to each other.
'umpire's decision' becomes 'out' (I can't explain this - if you can you should give a lot more credence to this answer).
'sighs' sounds like 'size'.
'size' put after 'out' is 'OUTSIZE'.
Can you help me to learn more?
(Other definitions for outsize that I've seen before include "Massive" , "big girl's blouse, for example?" , "Extra large (clothes)" , "Extra-large (garment)" , "Much larger than average, say clothes" .)