Mawson, C.O.S., ed. (1870–1938). Roget’s International Thesaurus. 1922.

Class V. Words Releasing to the Voluntary Powers
Division (I) Individual Volition
Section IV. Antagonism
2. Active Antagonism

711. Auxiliary.

   NOUN:AUXILIARY; recruit; assistant; adjuvant, adjutant; ayudante [Sp. Amer.], co-aid; adjunct; help, helper, helpmate, helping hand; colleague, partner, mate, confrère, coöperator; coadjuvant, coadjutant, coadjutator [rare], coadjutor, coadjutrix, collaborator.
  ALLY; friend [See Friend]; confidant (fem. confidante), fidus Achates [L.], alter ego [L.], pal [slang], chum [colloq.], mate, comate.
  aide-de-camp [F.], secretary, clerk, associate, marshal; right-hand, right-hand man; candleholder, bottle-holder [colloq.]; handmaid; servant [See Servant].
  PUPPET, cat’s-paw, creature, jackstraw, tool; jackal; âme damnée [F.]; satellite, adherent; parasite, dependent, client [Rom. hist.].
  CONFEDERATE; complice [archaic], accomplice; accessory, – after the fact; particeps criminis [L.]; socius criminis [L.].
  UPHOLDER; votary; sectarian, sectary; seconder, backer, supporter, abettor, advocate, partisan, champion, patron, friend at court, mediator; angel [slang].
  FRIEND IN NEED, jack at a pinch, special providence, deus ex machinâ [L.], guardian angel, fairy godmother, tutelary genius.
  1. A friend in need is a friend indeed.
  2. Of every friendless name the friend.—Johnson
  3. The best-condition’d and unwearied spirit In doing courtesies.—Merchant of Venice.