She gives expression of surprise about label being back to front (6)
I believe the answer is:
agatha
'she' is the definition.
'expression of surprise about label being back to front' is the wordplay.
'expression of surprise' becomes 'aha' (I've seen this before).
'about' indicates putting letters inside.
'label' becomes 'tag' ('tag' can be a synonym of 'label').
'being back to front' says the letters should be written in reverse.
'aha' enclosing 'tag' is 'ahtaga'.
'ahtaga' in reverse letter order is 'AGATHA'.
'gives' is the link.
(Other definitions for agatha that I've seen before include "...... Christie, author" , "Writer who created Hercule Poirot, . . . . . . Christie" , "- - Christie (lit.)" , "Aunt of Wooster" , "...... Christie wrote great detective stories" .)