Mindful means paying close, unjudging attention to now. Mindful breathing, be mindful of, mindful practice.
The older and plainer sense is simply keeping something in mind — mindful of the cost. The meditative sense came into English through translations of Buddhist texts and now dominates, with mindfulness taught in clinics and workplaces. Note that the Old English word meant of good memory, which is closer to the older sense.
1adjectivemindfulPaying close, unjudging attention to the present.
“She takes a mindful walk each morning, noticing every sound and smell around her.”
2adjectivekeepingKeeping something in mind.
“Mindful of the time, she kept her speech short.”
mindful is a quality of attention.
Old English gemyndful is mind plus -ful, and meant having a good memory. The attention sense arrived through translations of Buddhist teaching.
Old English
ġemyndful — of good memory
Middle English
myndeful
English, today
mindful
From Middle English myndeful, myndefull, from Old English ġemyndful (“of good memory”), equivalent to mind + -ful.
Etymology from Wiktionary, CC BY-SA