First lady Truman (4)
I believe the answer is:
bess
'first lady truman' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for bess that I've seen before include "Nickname for English queen" , "Our Good Queen" , "Queen Elizabeth 1 (sl)" , "Black - was Dick Turpin's horse" , "George Gershwin opera 'Porgy and . . . .'" .)