Semi-smile

She curled her pink lips upward in a shy semi-smile.

I saw him glance at his wife, and she gave a semi-smile of approval.

He stood looking at nothing in particular, with the blushing, awkward air and semi-smile which are common to shy boys when in company, -- very much as if they had come into the world by mistake, and found it in a degree of undress that was quite embarrassing.