a bit more; a little longer
Casual spoken variant of もう少し. Used to request or express a small additional amount, time, or degree.
See also: もう少し
Please wait a little longer.
もうちょっと大きいサイズはありますか。
Do you have a slightly larger size?
Contraction of もう (more) and 一寸 (ちょっと, a little).