Verb – Smudge
1 (+ object) : to make a dirty mark, spot, streak, etc., on (something)
Don’t smudge the picture with your dirty hands!
His face was smudged with grease.
2 a (no object) : to become blurry and unclear by being touched or rubbed
Charcoal drawings smudge easily.
2 b (+ object) : to make (something) blurry or unclear by touching or rubbing it
Be careful not to smudge (=smear) the ink.