Roman garb, so to speak (5)
I believe the answer is:
togas
'roman garb' is the definition.
(I've seen this in another clue)
'so to speak' is the wordplay.
'so' becomes 'as' (e.g. phrases like 'not as tall' and 'not so tall').
'to' says to put letters next to each other (I've seen this in other clues).
'speak' becomes 'tog' (I am not sure about this - if you are sure you should believe this answer much more).
'as' put after 'tog' is 'TOGAS'.
Can you help me to learn more?
(Other definitions for togas that I've seen before include "clothing" , "What some ancient citizens wore" , "garments worn by ancient Romans" , "Roman garments" .)