Daughter finds strange instrument (4)
I believe the answer is:
drum
'instrument' is the definition.
(I know that Drum is a instrument)
'daughter finds strange' is the wordplay.
'daughter' becomes 'd' (genealogical abbreviation).
'finds' means one lot of letters go next to another.
'strange' becomes 'rum' (synonyms).
'd'+'rum'='DRUM'
(Other definitions for drum that I've seen before include "See 16" , "Percussion instrument" , "See 18" , "Tap" , "nightclub" .)