The Collaborative International Dictionary of English v.0.48:
Sunburn \Sun"burn`\, v. t. [imp. & p. p. Sunburnedor Sunburnt; p. pr. & vb. n. Sunburning.] To burn or discolor by the sun; to tan. [1913 Webster] Sunburnt and swarthy though she be. --Dryden. [1913 Webster]WordNet (r) 3.0 (2006):
sunburnt adj 1: suffering from overexposure to direct sunlight [syn: sunburned, sunburnt]