After losing first point, observes sign of positivity (3)
I believe the answer is:
yes
'sign of positivity' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'after losing first point observes' is the wordplay.
I cannot really see how this works, but
'point' could be 's' (South) and 's' is present in the answer.
The remaining letters 'ye' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for yes that I've seen before include "Affirmative reply" , "Indeed" , "Oui" , "Aye" , "I agree" .)