Religious, holding cross passionately (5)
I believe the answer is:
hotly
'passionately' is the definition.
(I've seen this in another clue)
'religious holding cross' is the wordplay.
'religious' becomes 'holy' (I've seen this in another clue).
'holding' indicates putting letters inside.
'cross' becomes 'T' (shape).
'holy' enclosing 't' is 'HOTLY'.
(Other definitions for hotly that I've seen before include "in an ardent manner" , "Heatedly" , "With zeal - as one may be pursued" , "disputed thus?" , "showing passion" .)