Take steps to keep mug with a tumbler (7)
I believe the answer is:
acrobat
'tumbler' is the definition.
(synonyms)
'take steps to keep mug with a' is the wordplay.
'take steps' becomes 'act' (synonyms).
'to keep' is an insertion indicator.
'mug' becomes 'rob' (I've seen this in other clues).
'with' says to put letters next to each other.
'rob'+'a'='roba'
'act' placed around 'roba' is 'ACROBAT'.
(Other definitions for acrobat that I've seen before include "Performing gymnast" , "circus artiste" , "Tumbler" , "Spectacular gymnast" , "Gymnastic performer" .)