Letters that make sub-rosa
s, a, o, b, r, u are letters that make 'sub-rosa'
1 possible definitions for 'sub-rosa'
Under this definition, sub-rosa is an adjective and has the following properties:
under-the-table, behind-the-scenes have the same meaning as 'sub-rosa'
covert is similar to sub-rosa.
"a sub-rosa report", "has their under-the-table backing"