Use 'spiritless' to describe someone's temporary mood rather than their overall personality. After hearing the bad news, he became spiritless for the rest of the day.
Pro Tip 2/3
Subdued Energy
'Spiritless' can imply a lack of visible energy or excitement in someone's actions. His spiritless nod barely conveyed agreement.
Pro Tip 3/3
Not Depressed
Be careful not to confuse 'spiritless' with depression, which is more serious and long-term. She's not depressed, just feeling a bit spiritless today.