Strong and energetic (8)
![Ross](/clue/static/ross-mug.min.png)
'strong and energetic' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for vigorous that I've seen before include "Full of energy and strength" , "Strong, healthy" , "Powerful, energetic" , "Energetic, forceful" , "Strong and energetic" .)
(Other definitions for virile that I've seen before include "Robustly masculine" , "Potent" , "male" , "Masculine and macho" , "Manly, strong" .)