Lying hidden in US city shelter (6)
I believe the answer is:
latent
'lying hidden' is the definition.
(I've seen this in another clue)
'us city shelter' is the wordplay.
'us city' becomes 'LA' (abbreviation for Los Angeles).
'shelter' becomes 'tent' (canvas shelter).
'la'+'tent'='LATENT'
'in' is the link.
(Other definitions for latent that I've seen before include "Hidden (talent)" , "Concealed - not yet developed" , "'Hidden, undeveloped (6)'" , "Indiscernible" , "Potential but not active" .)