Lady first to encourage and tend soldiers (7)
I believe the answer is:
eleanor
'lady' is the definition.
(I've seen this before)
'first to encourage and tend soldiers' is the wordplay.
'first to' indicates taking the first letters.
'and' is a charade indicator (letters next to each other).
'tend' becomes 'lean' ('lean' can be a synonym of 'tend').
'soldiers' becomes 'or' (Other Rank).
The first letter of 'encourage' is 'e'.
'e'+'lean'+'or'='ELEANOR'
(Other definitions for eleanor that I've seen before include "Wife of F. D. Roosevelt" , "Name used in Beatles song" , "Miss Rigby" , "girl" , "Female" .)