Synonyms for Talk off top of head:

• v.

  •ramble (verb)
  • get off the subject,
  • Excurse,
  • lose the thread,
  • harp on,
  • beat around bush,
  • talk nonsense,
  • rant and rave,
  • be diffuse.
  •talk aimlessly, endlessly (verb)
  • ramble.

• Other synonyms:

  •Other relevant words:
  • amplify,
  • babble,
  • blather,
  • chatter,
  • depart,
  • descant,
  • digress,
  • divagate,
  • diverge,
  • drift,
  • drivel,
  • dwell on,
  • enlarge,
  • expatiate,
  • gossip,
  • maunder,
  • meander,
  • prose,
  • protract,
  • rattle on,
  • stray,
  • wander,
  • go astray,
  • go off on tangent,
  • go on and on,
  • talk randomly.

Antonyms for Talk off top of head:

• v.

  • ramble
    curtail, be direct, compress, go direct, abridge, stay, lessen, decrease, reduce, condense, shorten.