It is possible that there is a relationship between guuya-li ‘(will)shine’ and guuyay ‘mood’.
The mood words in GR do not always map easily onto English mood words and usages. It is likely that moods/emotions were more often expressed by verbs than by adjectives, e.g. Yuwaalaraay (YR) walindja-li ‘will be lonely’. With the children in our early learning program we are starting with simple structures.
The question ‘Are you in a good/bad mood?’ is Yaama nginu gaba/gagil guuyay?, literally ‘Question your good/bad/mood’. (The use of Yaama was traditionally only as a question word, not as a greeting).
Background about some of the words:
bina guwaal - bina ‘ear’ is important in GR and related languages for behaviour, related to winanga-li ‘(will) hear, understand, love, etc. It is possible that guwaal means ‘talk’.
gagilbiyal - gagil ‘bad’ and possibly biyal ‘having’.
ganagiil - probably from gana ‘liver’ (and possibly giil ‘piss’).
gayn.gayn - also means ‘smooth’, from gayn ‘scraper’.
warranggal - possibly from warra-y ‘(will) stand’.