Demand or require (4)
I believe the answer is:
need
This clue is a double definition.
'demand' is the first definition.
(I know that demand can be written as need)
'require' is the second definition.
(I know that require can be written as need)
(Other definitions for need that I've seen before include "Distressful situation" , "Exigency" , "''A friend in .... is a friend indeed''" , "Call" , "Desideratum" .)