due
noun
that which is deserved or owed
“give the devil his due”
a payment that is due (e.g., as the price of membership)
“the society dropped him for non-payment of dues”
adjective
owed and payable immediately or on demand
“payment is due”
Oppositesunduescheduled to arrive
“the train is due in 15 minutes”
suitable to or expected in the circumstances
“all due respect”
“due cause to honor them”
Oppositesunduecapable of being assigned or credited to
“punctuation errors ascribable to careless proofreading”
“the cancellation of the concert was due to the rain”
adverb
directly or exactly; straight
“went due North”
Source: WordNet 3.1, Princeton University