In safe? (2,4)
I believe the answer is:
at home
This clue could be a double definition.
'in' is the first definition.
(someone at home is 'in')
'safe?' is the second definition.
Both the definition and answer are singular nouns.
Maybe you can see a link between them that I can't see?
Can you help me to learn more?
(Other definitions for at home that I've seen before include "Oh mate! (anag)" , "In (for a party?)" , "ready to receive visitors" , "celebration" , "In one's own house" .)