semi-smile

plural semi-smiles

1. A faint smile.

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

   2004, Susan M. Kirschbaum, “Frills and Chills”, in The New York Observer

   1 more example

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

   1874, Mrs. Macquoid, Appletons' Journal: Volume 12, D. Appleton & Co., page 623

2. A suppressed or forced smile.

   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.

   2008, Charles H. Sylvester, Journeys Through Bookland, Volume 7, Wildside Press, page 34