Of an event or circumstance. Occurring by chance and resulting in a favourable outcome; fortuitous.

bringing about a happy outcome entirely by chance or good luck; fortunate.

That is, or is thought to be, brought about by special intervention of Providence; opportune, lucky.

Covered with jam, sticky. Also figurative (colloquial), excellent; very lucky or profitable; easy, ‘soft’.

(The more usual sense.) Applied to discoveries, meetings, etc., of this kind.