Synonyms for By chance:

• adj.

  •casual (adjective)
  • un-expected,
  • more serendipitous,
  • un intentional,
  • un foreseen,
  • in-frequent,
  • un-foreseen,
  • un premeditated,
  • un-premeditated,
  • un expected,
  • un-intentional,
  • in frequent,
  • un planned,
  • most serendipitous,
  • un-planned.
  •hit or miss (adjective)
  • more haphazardly,
  • hit miss,
  • most haphazardly.

• adv

  •accidentally (adverb)
  • casually.

• adv.

  •all (adverb)
  • perchance,
  • by chance.
  •by accident (adverb)
  • unwittingly,
  • unexpectedly,
  • for some reason,
  • by coincidence,
  • fortuitously,
  • out of the clear blue sky,
  • unintentionally,
  • as luck would have it,
  • by a fluke,
  • by mistake.
  •casually (adverb)
  • un-intentionally,
  • in advertently,
  • un intentionally,
  • in-advertently.
  •haphazardly (adverb)
  • in-constantly,
  • in constantly.

• n.

  •accidentally (noun)
  • accidentally.
  •by chance (noun)
  • haply,
  • by luck,
  • circumstantially,
  • incidentally.

• Other synonyms:

  •
  • unnecessarily.
  •Other relevant words:
  • unpredictably,
  • spontaneously,
  • random,
  • now and then,
  • indefinitely,
  • at intervals,
  • capriciously,
  • unsystematically,
  • in snatches,
  • irregularly,
  • peradventure,
  • sporadically,
  • inadvertently,
  • at a venture,
  • in some way,
  • unmethodically,
  • fitfully,
  • carelessly,
  • arbitrarily,
  • Unpremeditatedly,
  • by fits,
  • sloppily,
  • accident,
  • spasmodically,
  • in spots,
  • Desultorily,
  • at haphazard,
  • indiscriminately,
  • by snatches,
  • somehow,
  • promiscuously,
  • serendipitously,
  • involuntarily,
  • adventitiously,
  • by accident,
  • occasionally,
  • as it chanced,
  • erratically.

Antonyms for By chance:

• adv.

  • Other antonyms:
    designedly, by design, deliberately, on purpose, purposely, advisedly, by choice.