Synonyms for Do one's bit:

• v.

  •contribute (verb)
  • redound,
  • sit in on,
  • be conducive,
  • have a hand in,
  • finger in the pie,
  • support,
  • get in the act,
  • be instrumental.
  •pitch in (verb)
  • contribute,
  • go to it,
  • tee off,
  • jump in,
  • subscribe,
  • chip in,
  • DO,
  • begin,
  • set about,
  • join in,
  • fall to,
  • tackle,
  • volunteer,
  • get cracking,
  • come through,
  • launch,
  • plunge into,
  • attack,
  • participate,
  • help; get busy,
  • hop to it,
  • commence,
  • buckle down,
  • set to,
  • cooperate,
  • contribute work,
  • wade in,
  • lend a hand,
  • get going.

• Other synonyms:

  •pitch in
  • co-operate,
  • pitch in,
  • joining in,
  • co-operated,
  • teed off,
  • Volunteering,
  • getting going,
  • got going,
  • co-operating,
  • joined in,
  • co-operates,
  • hop it.

Antonyms for Do one's bit:

• v.

  • contribute
    harm, subtract, decrease, neglect, hinder, withdraw, counteract, withhold, injure, take, stop, take away, shun, disapprove, weaken, oppose, hurt.
  • pitch in
    prevent.