Entry revised for OED Online

[Etym. unknown. Numerous conjectures have been made about the origin of the word but all lack foundation.] 

    1. An ‘elderly’ naval officer.
 
  1941 C. GRAVES Life Line 143 Their ages are as youthful as air crews. Thirty-two is considered the maximum... In H.M.S. Wasps' Nest, anyone aged thirty-two is officially a ‘boffin’. There is even a song about them... ‘He glares at us hard and he scowls, For we're the Flotilla Boffins.’ 1942 ‘SEA-WRACK’ Random Soundings 71 We were ‘Old Boffins’, the Pay. and I. He had been in the Bank of England for many years, and in the R.N.R. almost as long... I hadn't been to sea in a professional capacity for some eighteen years.
 

    2. A person engaged in ‘back-room’ scientific or technical research. Hence boffin(e)ry, boffins collectively; also, the activity of a boffin.
  The term seems to have been first applied by members of the Royal Air Force to scientists working on radar.
 
  1945 Times 15 Sept. 5/4 A band of scientific men who performed their wartime wonders at Malvern and apparently called themselves ‘the boffins’. 1948 ‘N. SHUTE’ No Highway iii. 61 ‘What's a boffin?’ ‘The man from Farnborough. Everybody calls them boffins. Didn't you know?’.. ‘Why are they called that?’.. ‘Because they behave like boffins, I suppose.’ 1948 LORD TEDDER in A. P. Rowe One Story of Radar p. vii, I was fortunate in having considerable dealings in 1938-40 with the ‘Boffins’ (as the Royal Air Force affectionately dubbed the scientists). 1952 Picture Post 30 Aug. 20/1 Only a backroom boffin out of touch with the classroom could hold this pious belief. 1954 Economist 19 June Suppl. 6/3 The graduate from researchroughly..the boffin of industry. 1957 R. WATSON-WATT Three Steps to Victory xxxiii. 201 The proud title of Boffin was first conferred on a few radar scientists by Royal Air Force officers with whom they worked in close co-operation... I am not quite sure about the true origins of this name of Boffin. It certainly has something to do with an obsolete type of aircraft called the Baffin, something to do with that odd bird, the Puffin; I am sure it has nothing at all to do with that first literary Back Room Boy, the claustrophiliac Colonel Boffin. 1958 Times Lit. Suppl. 14 Feb. 83/3 In one of those diverting interludes..he writes an anatomy of Boffinry. 1958 Economist 25 Oct. 298/1 The unexpected success of the boffins' conference at Geneva..ending in agreement on the feasibility of controlling a nuclear test suspension. 1960 J. MACLAREN-ROSS Until Day viii. 132, I was engaged in some boffinery in a blasted back-room unit.
 

    3. Brit. colloq. In weakened use: an intellectual, an academic, a clever person; an expert in a particular field; esp. such a person perceived as lacking practical or social skills. Cf. EGG-HEAD n.

 
  1954 Times 9 Nov. 10/6 (advt.) You may know a ‘buffoon’ from a ‘boffin’ but when it comes to choosing cloth you would do well to ask your tailor. 1959 Brit. Jrnl. Educ. Stud. 8 24 The man of learning..has been labelled a ‘swot’ or, in our own times, a ‘boffin’ or an ‘egg-head’. 1973 Statistician 22 205 I've been in the business man and boy for 30 years, and don't need any boffin to tell me how to run it. 1990 O. CHADWICK Michael Ramsey (1991) 73 The opinion of the world and society which thought of him as a boffin. 1993 Independent on Sunday 8 Aug. (Business section) 13/5 A third important sub-species [of currency dealers] is the options dealers, the boffins of the currency markets.