Noticed place was in bad mood (6)
I believe the answer is:
spleen
'mood' is the definition.
(spleen is a kind of mood)
'noticed place was in bad' is the wordplay.
I cannot really see how this works, but
'place' could be 'pl' (abbreviation used in postal addresses) and 'pl' is found within the answer.
'noticed' could be 'seen' (I've seen this in another clue) and 'seen' is found in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for spleen that I've seen before include "Ill-humour" , "Vent it to show anger" , "Peevishness, from bodily organ" , "Organ - that is vented!" , "The organ once thought to be the seat of anger" .)