Very slight (3)
(Other definitions for wee that I've seen before include "Tiny (Scot)" , "number one" , "Mini in Glasgow?" , "Minute" , "Slash" .)
'very slight' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for tenuous that I've seen before include "Sketchy" , "Very slight, with little substance or validity" , "Lacking substance or significance" , "Very slight (connection)" , "Flimsy, thin" .)