In leaf, can be grand at last (6)
I believe the answer is:
finale
'last' is the definition.
(synonyms)
'in leaf can be grand at' is the wordplay.
'in' is an insertion indicator.
'can be' is an anagram indicator.
'grand at' becomes 'in' (synonymous in some cases - eg at school, in school. I am not sure about the 'grand' bit.).
'leaf' with letters rearranged gives 'fale'.
'fale' placed around 'in' is 'FINALE'.
Can you help me to learn more?
(Other definitions for finale that I've seen before include "Conclusion of a performance" , "Last section of a musical composition" , "When it's grand, it's the last scene" , "Last song etc" , "Last act, movement" .)