Gymnastics expert almost satisfied and calm (8)
I believe the answer is:
peaceful
'calm' is the definition.
(associated in meaning)
'gymnastics expert almost satisfied' is the wordplay.
'gymnastics' becomes 'pe' (Physical Education).
'expert' becomes 'ace' (ace can informally mean very good).
'almost' means to remove the last letter (most of the word but not all of it).
'satisfied' becomes 'full' (e.g. after eating).
'full' with its final letter taken off is 'ful'.
'pe'+'ace'+'ful'='PEACEFUL'
'and' acts as a link.
(Other definitions for peaceful that I've seen before include "Amicable" , "Tranquil, calm" , "Not violent" , "Serene" , "Placid, not belligerent" .)