wavering
adj.moving from side to side or back and forth, often because of a lack of strength or confidence. You use this to describe someone who is not sure about their decision or a light that is flickering.
adj.moving unsteadily from side to side or back and forth, typically due to a lack of stability or resolve. Often describes physical movement or a fluctuation in opinion or belief.
“The candle flame was wavering in the wind.”
“The politician's wavering support for the new law caused many of his colleagues to lose confidence in his leadership.”
“As the sun began to set, the shadows of the trees became long and wavering, creating a sense of unease that settled over the quiet valley.”
From waver + -ing.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.