beau

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A male companion or friend with whom one has a sexual or romantic relationship.
• noun A dandy; a fop.

from The Century Dictionary.

• To act the beau to; attend or escort (a lady).
• Good; fair: used especially in address: as, “beau sir,” See beausire, beaupere, etc.
• noun (bōz).
• noun One who is very neat and particular about his dress, and fond of ornaments and jewelry; a fop; a dandy: now most often said of a man of middle age or older: as, he is an old beau.
• noun A man who is suitor to or is attentive to a lady; a lover; a swain.
• noun Synonyms Dandy, Exquisite, etc. See coxcomb.

from the GNU version of the Collaborative International Dictionary of English.

• noun A man who takes great care to dress in the latest fashion; a dandy.
• noun A man who escorts, or pays attentions to, a lady; an escort; a suitor or lover.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun dated A man with a reputation for fine dress and etiquette; a dandy or fop.
• noun dated A male lover; a boyfriend.
• noun A male escort.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a man who is much concerned with his dress and appearance
• noun a man who is the lover of a girl or young woman