platonic
adj.describing a close relationship between two people that is friendly and loving but does not involve sex.
adj.characterised by a close relationship that is spiritual or intellectual rather than physical or sexual. Often used to distinguish deep friendships from romantic or sexual partnerships.
“They have a strictly platonic relationship.”
“After their brief attempt at dating, they realized they were much better suited to a platonic friendship.”
“The film explores the nuances of a lifelong platonic bond, challenging the cultural assumption that a deep emotional intimacy must eventually lead to a romantic encounter.”
When referring to relationships, it is usually written with a lowercase 'p'; when referring to the philosophy of Plato, it is capitalised.
“This rollercoaster platonic relationship is with Stella, the girl she met at school shortly after moving from South Africa to the UK.”
“The platonic ideal for Starship is full reusability, with both the first and second stages returning to the launch site and being re-stacked for launch within hours.”
From Latin Platōnicus. By surface analysis, Platon (“Plato”) + -ic (“relating to”).
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.