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' means one lot of letters go next to another (I've seen this in other clues).
'speak' becomes 'tog' (I can't justify this - if you can you should give a lot more credence to this answer).
'as' 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" .)