Don't worry about US city getting cross (5)
I believe the answer is:
relax
'don't worry' is the definition.
(I've seen this before)
'us city getting cross' is the wordplay.
'us' becomes 're' (I am not sure about this - if you are sure you should believe this answer much more).
'city' becomes 'LA' (Los Angeles).
'getting' says to put letters next to each other.
'cross' becomes 'x' (X is cross-shaped).
're'+'la'+'x'='RELAX'
'about' is the link.
Can you help me to learn more?
(Other definitions for relax that I've seen before include "Unbend" , "Slacken" , "Put your feet up" , "Chill out" , "Don't worry" .)