The foreigner is a bit of a liability (3)
I believe the answer is:
ali
'a liability' is the definition.
Both the answer and definition are singular nouns.
Perhaps there's a link between them I don't understand?
'the foreigner is a bit of' is the wordplay.
'the foreigner' becomes 'al' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a bit of' says to take the initial letters.
The initial letter of 'is' is 'i'.
'al'+'i'='ALI'
Can you help me to learn more?
(Other definitions for ali that I've seen before include "girl shortly" , "Muhammad ___ (or MacGraw?)" , "Mohammad . . ., . . . Hewson" , "Former boxing champion" , "Lepidopterous floater, apian stinger, d. 2016" .)