That would be Cirrus clouds.
Cirrus clouds are thin, white, and feathery.
You may mean Cirrus clouds, characterised by thin wispy strands, they also have the common name of 'mares tails'.
Cirrus (Ci): The ice-crystal cloud is a feathery white cloud that is the highest in the sky. It has a wispy looking tail that streaks across the sky and is called a fallstreak. - Kidzworld dot com
A cirrus cloud can be described as wispy and feathery.
cirrus
Cirrus cloud
Cirrostratus clouds.
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cirrus
stratus
cirrus cloud (who didnt Know that) I didnt
cirrus