|Origin:||Latin instans, present participle of instare 'to stand on, be present', from stare 'to stand'|
1 [usually before noun]
happening or produced immediately [= immediate]:
an instant success
a system that provides instant access to client information
The women took an instant dislike to one another.
The programme brought an instant response.
2 [only before noun]DFF
instant food, coffee etc is in the form of powder and prepared by adding hot water: