Salacious dancing leaving us out? That's not very friendly (7)
I believe the answer is:
asocial
'not very friendly' is the definition.
(avoiding social interaction or socialising)
'salacious dancing leaving us out?' is the wordplay.
I cannot quite understand how this works, but
'dancing' could be 'social' (social dancing is a kind of dancing) and 'social' is found within the answer.
A single letter 'a' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
'that's' acts as a link.
(Other definitions for asocial that I've seen before include "lacking friendly instincts" , "avoiding contact with others" , "Avoiding company" , "without friends" , "not connected with community" .)