The Collaborative International Dictionary of English v.0.48:
Gainly \Gain"ly\, adv. [See Gain, a.] Handily; readily; dexterously; advantageously. [Obs.] --Dr. H. More. [1913 Webster]WordNet (r) 3.0 (2006):
gainly adj 1: graceful and pleasing; "gainly conduct"; "a gainly youth with dark hair and eyes"