lobsterman n.

large, long-tailed, stalk-eyed, 10-legged marine shellfish (Homarus vulgaris), early Middle English lopster, lopister, from Old English loppestre "lobster," also "locust," a corruption of Latin locusta, lucusta "marine shellfish, lobster;" also "locust, grasshopper," which is of unknown origin. De Vaan writes that "The only word similar in form and meaning is lacerta 'lizard; mackerel', but there is no common preform in sight. ... [T]hey could be cognate words in the language from which Latin borrowed these forms."

The change of Latin -c- to English -p- (and, from late 14c., to -b-) is unexplained; perhaps it is by influence of Old English loppe, lobbe "spider." The ending seems to have been altered by the old fem. agent noun suffix (preserved in Baxter, Webster, etc.; see -ster), which approximated the sound of Latin -sta.

OED says the Latin word originally meant "lobster or some similar crustacean, the application to the locust being suggested by the resemblance in shape." Trilobite fossils in Worcestershire limestone quarries were known colloquially as locusts, which seems to have been the generic word for "unidentified arthropod" (as apple was for "foreign fruit"). Locusta in the sense "lobster" also appears in Old Cornish legast and French langouste (12c.), now "crawfish, crayfish," but in Old French both "lobster" and "locust" (a 13c. psalter has God giving over the crops of Egypt to the langoustes).

As slang for "a British soldier" since 1640s, originally in reference to the jointed armor of the Roundhead cuirassiers, later (1660) to the red coat, the color of a boiled lobster.

Sir William Waller having received from London [in June 1643] a fresh regiment of five hundred horse, under the command of sir Arthur Haslerigge, which were so prodigiously armed that they were called by the other side the regiment of lobsters, because of their bright iron shells with which they were covered, being perfect curasseers. [Lord Clarendon, "History of the Rebellion," 1647]

"a featherless plantigrade biped mammal of the genus Homo" [Century Dictionary], Old English man, mann "human being, person (male or female); brave man, hero;" also "servant, vassal, adult male considered as under the control of another person," from Proto-Germanic *mann- (source also of Old Saxon, Swedish, Dutch, Old High German man, Old Frisian mon, German Mann, Old Norse maðr, Danish mand, Gothic manna "man"), from PIE root *man- (1) "man." For the plural, see men.

Sometimes connected to root *men- (1) "to think," which would make the ground sense of man "one who has intelligence," but not all linguists accept this. Liberman, for instance, writes, "Most probably man 'human being' is a secularized divine name" from Mannus [Tacitus, "Germania," chap. 2], "believed to be the progenitor of the human race."

Specific sense of "adult male of the human race" (distinguished from a woman or boy) is by late Old English (c. 1000); Old English used wer and wif to distinguish the sexes, but wer began to disappear late 13c. and was replaced by man. Universal sense of the word remains in mankind and manslaughter. Similarly, Latin had homo "human being" and vir "adult male human being," but they merged in Vulgar Latin, with homo extended to both senses. A like evolution took place in Slavic languages, and in some of them the word has narrowed to mean "husband." PIE had two other "man" roots: *uiHro "freeman" (source of Sanskrit vira-, Lithuanian vyras, Latin vir, Old Irish fer, Gothic wair; see *wi-ro-) and *hner "man," a title more of honor than *uiHro (source of Sanskrit nar-, Armenian ayr, Welsh ner, Greek anēr; see *ner- (2)).

Man also was in Old English as an indefinite pronoun, "one, people, they." It was used generically for "the human race, mankind" by c. 1200. As a word of familiar address, originally often implying impatience, c.1400; hence probably its use as an interjection of surprise or emphasis, since Middle English but especially popular from early 20c.

As "a woman's lover," by mid-14c. As "adult male possessing manly qualities in an eminent degree," from 14c. Man's man, one whose qualities are appreciated by other men, is by 1873. Colloquial use of the Man for "the boss" is by 1918. To be man or mouse "be brave or be timid" is from 1540s. Meaning "piece with which a game (especially chess) is played" is from c. 1400.

Man-about-town "man of the leisure who frequents clubs, theaters, and other social resorts" is from 1734. Man of the world is from mid-14c. as "secular man, layman;" by early 15c. as "man experienced in the ways of the world, one able to take things in stride." To do something as one man "unanimously" is from late 14c.

So I am as he that seythe, 'Come hyddr John, my man.' [1473]

MANTRAP, a woman's commodity. [Grose, "Dictionary of the Vulgar Tongue," London, 1785]

At the kinges court, my brother, Ech man for himself. [Chaucer, "Knight's Tale," c. 1386]