Social skill (5)
(Other definitions for charm that I've seen before include "Delightfulness" , "Attractive manner" , "Lure" , "Campaign to gain support and become more popular" , "small ornament" .)
'social skill' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tact that I've seen before include "measure of diplomacy?" , "Consideration and sensitivity" , "Understanding" , "Sensitivity, diplomacy" , "Delicacy of feeling, skill in saying the right thing" .)