A pet form of the name Robert. Hence, perhaps, the use of the word, in various combinations, denoting persons: as dry-bob, a boy (at Eton) who devotes himself to land-sports, as cricket, football, etc.; wet-bob, one who devotes himself to boating; light-bob, a soldier of the light infantry, or of a light company.
1721. Mrs. Centlivre, Platon. Lady, Epil. Some Cheapside-Bobbs too trudge it to our play.
1844. W. H. Maxwell, Sports & Adv. Scotl., xxxv. (1855), 282. Me, that never listened to a light-bob.
1848. Thackeray, Van. Fair, xxiv. (1853), 192. Mr. Stubble, as may be supposed from his size and slenderness, was of the Light Bobs.
1865. W. L. C., Etoniana, xi. 172. Of course a dry-bob boats occasionally, and a wet-bob plays cricket, for his amusement.
1886. Sat. Rev., 27 March, 438/1. Reformed Eton. What avails it , if we are not even informed whether he is a wet bob or a dry bob?