A chap holding mug and tumbler (7)
I believe the answer is:
acrobat
'tumbler' is the definition.
(synonyms)
'a chap holding mug' is the wordplay.
'chap' becomes 'cat' (I've seen this in other clues).
'holding' indicates putting letters inside.
'mug' becomes 'rob' (to mug someone is to rob them).
'cat' enclosing 'rob' is 'crobat'.
'a'+'crobat'='ACROBAT'
'and' is the link.
(Other definitions for acrobat that I've seen before include "Agile circus performer" , "Tightrope-walker" , "Athletic type" , "Tumbler" , "Performer going head over heels?" .)