Saw a daughter getting silver, second in heptathlon (5)
I believe the answer is:
adage
'saw' is the definition.
(synonyms)
'a daughter getting silver second in heptathlon' is the wordplay.
'a daughter' becomes 'ad' (I've seen this in other clues).
'getting' means one lot of letters go next to another.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'second in heptathlon' becomes 'e' (2nd letter of 'heptathlon').
'ad'+'ag'+'e'='ADAGE'
(Other definitions for adage that I've seen before include "Axiom" , "True proverb or saying" , "Old saying, maxim" , "Saw, proverb" , "Short statement expressing a general truth" .)