flesh sth out, put flesh on the bones of

Bildunterschrift: Großansicht des Bildes mit der Bildunterschrift: Sarkozy and Brown began working as their countries' finance ministers

Sarkozy said the friendship betwefleshen Britain and France "shouldn't simply be a matter of principle," but one that is "fleshed out by concrete projects on the economy, immigration, security, defense."

'Things I've Been Silent About'

By AZAR NAFISI
Reviewed by ELAINE SCIOLINO

The author of “Reading Lolita in Tehran” fleshes out personal stories left untold or half-told in her earlier work.

flesh sth out phrasal verb [M]
to add more details or information to something:
These plans need to be fleshed out with some more figures before the committee votes on them.

Also, put flesh on the bones of. Give substance to, provide with details, amplify. For example, The editor told her to flesh out the story, or You need to put flesh on the bones of these characters. This metaphoric expression, alluding to clothing a nude body or adding flesh to a skeleton, was in the mid-1600s put simply as to flesh, the adverb out being added about two centuries later.