Marijuana sent up by party girl for head honcho (3,3)
I believe the answer is:
top dog
'head honcho' is the definition.
'marijuana sent up by party girl' is the wordplay.
'marijuana' becomes 'pot' (synonyms).
'sent up' says the letters should be written in reverse.
'by' is a charade indicator (letters next to each other).
'party' becomes 'do' (do is a kind of party).
'girl' becomes 'g'.
'pot' backwards is 'top'.
'top'+'do'+'g'='TOP DOG'
'for' is the link.
Can you help me to learn more?
(Other definitions for top dog that I've seen before include "big cheese?" , "Crufts champion" , "Leading light (informal)" , "Person in charge" , "one who's most successful" .)