Friendless, having abandoned east side of capital for city in Cambs (6)
I believe the answer is:
lonely
'friendless' is the definition.
(thesaurus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for lonely that I've seen before include "In need of companionship" , "withdrawn" , "Solitary, lacking company" , "Solitary and sad" , "By oneself" .)