Flower you and I name first (5)
I believe the answer is:
tagus
'flower' is the definition.
(Tagus is an example)
'you and i name first' is the wordplay.
'you and i' becomes 'us' (the two of us).
'name' becomes 'tag' (I've seen this in other clues).
'first' says to put letters next to each other.
'us' after 'tag' is 'TAGUS'.
(Other definitions for tagus that I've seen before include "currently moving through SW Europe?" , "banker" , "Portuguese river flowing to sea near Lisbon" , "Longest river of Iberian peninsula" , "Portugese river" .)