Additive makes limber lads tango (10)
I believe the answer is:
supplement
'additive' is the definition.
(I've seen this before)
'limber lads tango' is the wordplay.
'limber' becomes 'supple' (synonyms).
'lads tango' becomes 'ment' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'supple'+'ment'='SUPPLEMENT'
'makes' is the link.
Can you help me to learn more?
(Other definitions for supplement that I've seen before include "Add to (something)" , "Add to; newspaper section" , "Something added" , "Boost" , "something to remedy a deficiency" .)