Bashful

Examples of usage:

1. They were all good- looking, but shy and bashful to a degree I never before witnessed.
   "Three Months in the Southern States, April-June 1863", Arthur J. L. (Lieut.-Col.) Fremantle.
2. And with that he springs a bashful smile.
   "Torchy, Private Sec.", Sewell Ford.
3. So if anyone wants to do his business, there's no call to be bashful about it.
   "The Satyricon, Complete", Petronius Arbiter.