No longer be able to do or handle something skillfully. For example,
I used to make beautiful cakes but I seem to have lost my touch, or
Dad had a real knack for letting someone down gently, but he's lost his touch. This expression alludes to the older sense of
touch as a musician's skill on an instrument or an artist's skill in using a brush or chisel. [First half of 1900s] Also see
lose touch.