Strainer is taken up by First Lady (5)
I believe the answer is:
sieve
'strainer' is the definition.
(sieve is a kind of strainer)
'is taken up by first lady' is the wordplay.
'taken up' shows that the letters should be reversed in order.
'by' says to put letters next to each other.
'first lady' becomes 'eve' (first woman in the Bible).
'is' in reverse letter order is 'si'.
'si'+'eve'='SIEVE'
(Other definitions for sieve that I've seen before include "Utensil with holes for straining" , "particle separator" , "Wire mesh utensil" , "Screen, sift, strain" , "Craft for Jumblies" .)