Giving permission, or predisposed to give it; lenient.
For neither Man nor Angel can discern / Hypocrisy, the only evil that walks / Invisible, except to God alone, / By his permissive will, through Heaven and Earth;1667, John Milton, “Book 3”, in Paradise Lost, lines 682–685; republished as John Bradshaw, editor, The Poetical Works of John Milton, 2nd edition, volume 2, London: William H. Allen & Company, 1885, page 85:
"Permissive" working allows more than one train to be in a block section at one time but trains must be run at low speed in order to stop on sight behind the train in front. Such working is often authorised to allow freight trains to "bunch" together to await a path through a bottleneck instead of being strung out over several block sections, as would be necessary if absolute working were in force.1962 October, “Talking of Trains: The collisions at Connington”, in Modern Railways, page 232:
1 more example
More to the point: 20 years ago, I did not perceive a political dimension to parenting. Some parents were too strict, some parents were too permissive and some parents were just right — and I saw no connection between parenting style and parental politics.2026 March 4, Leonard Sax, “Permissive parents skew left, strict ones right — US parenting has become political like never before”, in New York Post:
2
Of a footpath Open to the public by permission of the landowner.
Bridleway or similar
Many permissive paths work well and have done for a significant amount of time, enhancing or connecting our network of public footpaths, byways and bridleways, however unevenly distributed.2026 February 7, Leonie Helm, “"I’ve always loved a ‘permissive path’ – it’s always seemed like the nicest of invitations."”, in Countryfile:
3
Biology, Natural sciences That allows the replication of viruses.