Conditional
Definition 1 of 3
Pro Tip 1/3
Expect Constraints
The adjective 'conditional' implies restrictions are present for an event to occur. Your job offer is conditional upon the successful background check.
Pro Tip 2/3
Uncertain Outcome
'Conditional' suggests the future is not set and depends on certain requirements. He could join the trip, conditional on his recovery.
Pro Tip 3/3
Not Guaranteed
Use 'conditional' to indicate something promised may not happen. The bonus is conditional, not guaranteed.