1. reverses or cancels the effect of something that has been done
Usage: third person singular present tense of ‘undo’
2. unfastens or opens something that has been fastened or closed
Usage: third person singular present tense of ‘undo’
3. causes the ruin or downfall of someone or something
Usage: third person singular present tense of ‘undo’

Examples

• She undoes her shoelaces before taking off her shoes.
• The new policy undoes years of progress in environmental protection.
• He carefully undoes the knot in the rope.
• One mistake undoes all his hard work.
• The software undoes the last action when you press the button.
• Pride often undoes even the most successful people.
• She undoes the clasp on her necklace.