Straightaway has 6 different meanings across 3 categories:
a straight segment of a roadway or racecourse
A straight section of a racetrack.
performed with little or no delay
"an immediate reply to my letter"
"a prompt reply"
"was quick to respond"
"a straightaway denial"
Extending into the distance in a straight line.
without delay or hesitation; with no time intervening
"he answered immediately"
"found an answer straightaway"
"an official accused of dishonesty should be suspended forthwith"
"Come here now!"
Alternative form of straight away (“at once; immediately”)