Sickly-looking sons touring each city in Wales (7)
I believe the answer is:
swansea
'in wales' is the definition.
('Swansea' is part of 'wales')
'sickly-looking sons touring each' is the wordplay.
'sickly-looking' becomes 'wan' (I've seen this in another clue).
'sons' becomes 'ss' (s is abbreviation for son).
'touring' indicates putting letters inside (touring can mean going round).
'each' becomes 'ea' (abbreviation).
'wan' inserted within 'ss' is 'swans'.
'swans'+'ea'='SWANSEA'
'city' acts as a link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for swansea that I've seen before include "coastal location" , "Second city of Wales" , "Welsh city" , "South Wales city" , "Welsh port" .)