Synonyms for Straight away:

• adv.

  •immediately (adverb)
  • instantaneously,
  • promptly,
  • in a flash,
  • forthwith,
  • on the double,
  • soon,
  • straight off,
  • shortly,
  • pronto,
  • rapidly.
  •instantly (adverb)
  • right away.
  •punctually (adverb)
  • sharply,
  • speedily,
  • expeditiously,
  • punctually,
  • swiftly,
  • precisely,
  • quickly.

• Other synonyms:

  •
  • suddenly,
  • now,
  • summarily,
  • directly.
  •
  • quick.
  •
  • right.
  •Other relevant words:
  • like greased lightning,
  • straightway,
  • in a wink,
  • right off,
  • double-quick,
  • outright,
  • apace,
  • nail,
  • like a shot,
  • in short order,
  • hastily,
  • on the nail,
  • in a moment,
  • once,
  • p.d.q.,
  • in haste,
  • momentarily,
  • post-haste,
  • precipitately,
  • in a trice,
  • like lightning,
  • Lickety Split,
  • hurriedly.

Antonyms for Straight away:

• adv.

  • immediately
    later, never, eventually.
  • readily
    unwillingly, Difficultly, grudgingly.
  • right
    incorrectly, inappropriately, unfairly, unjustly, indirectly, unsuitably, inaccurately, wrongly.