favorable

1. Advantageous; helpful: favorable winds.
2. Encouraging; propitious: a favorable diagnosis.
3. Manifesting approval; commendatory: a favorable report.
4. Winning approval; pleasing: a favorable impression.
5. Granting what has been desired or requested: a favorable reply.
6. Indulgent or partial: listened with a favorable ear.

SYNONYMS   favorable, propitious, auspicious, benign, conducive. These adjectives describe what is indicative of a successful outcome. Favorable can refer to what contributes in a positive way to the attainment of a goal: a favorable review. Propitious implies a favorable tendency or inclination: "Miracles are propitious accidents" (George Santayana). Auspicious refers to what presages good fortune: an auspicious beginning. Benign applies to people or things that exert a beneficial influence: "I lingered round them, under that benign sky . . . and wondered how anyone could ever imagine unquiet slumbers, for the sleepers in that quiet earth" (Emily Brontë). Something conducive leads or contributes to a result, often a desirable one: a quiet place conducive to reading.

adjective

1. Affording benefit: advantageous, benefic, beneficent, beneficial, benignant, good, helpful, profitable, propitious, salutary, toward, useful. See help/harm/harmless.
2. Occurring at a fitting or advantageous time: auspicious, opportune, propitious, prosperous, seasonable, timely, well-timed. See luck/misfortune/chance.
3. Indicative of future success or full of promise: auspicious, benign, bright, brilliant, fair, fortunate, good, propitious. See luck/misfortune/chance.
4. To one's liking: agreeable, congenial, good, grateful, gratifying, nice, pleasant, pleasing, pleasurable, satisfying, welcome. See like/dislike.
5. Giving assent: affirmative, positive. See affirm/deny/argue.
6. Disposed to favor one over another: partial, preferential. See fair/unfair.

Definition: approving, friendly
Antonyms: bad, disagreeable, unfavorable, unfriendly, unpromising

adj

Definition: good, timely, advantageous
Antonyms: bad, derogatory, detrimental, harmful, hindering, hurtful, hurting, injurious, unfavorable, unhelpful

The adjective has 7 meanings:

Meaning #1: very favorable or advantageous
  Synonyms: advantageous, golden

Meaning #2: encouraging or approving or pleasing
  Synonym: favourable
  Antonym: unfavorable (meaning #1)

Meaning #3: (of winds or weather) tending to promote or facilitate
  Synonym: favourable
  Antonym: unfavorable (meaning #2)

Meaning #4: favorably disposed; not antagonistic
  Synonym: well-disposed

Meaning #5: tending to favor or bring good luck
  Synonyms: auspicious, encouraging, favourable, lucky, prosperous

Meaning #6: at a convenient or suitable time
  Synonyms: favourable, opportune

Meaning #7: granting what has been desired or requested
  Synonym: positive