The Collaborative International Dictionary of English v.0.48:

Swooning \Swoon"ing\,
   a. & n. from Swoon, v. -- Swoon"ing*ly, adv.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Swoon \Swoon\, v. i. [imp. & p. p. Swooned; p. pr. & vb. n.
   Swooning.] [OE. swounen, swoghenen, for swo?nien, fr.
   swo?en to sigh deeply, to droop, AS. sw[=o]gan to sough,
   sigh; cf. gesw[=o]gen senseless, swooned, gesw[=o]wung a
   swooning. Cf. Sough.]
   To sink into a fainting fit, in which there is an apparent
   suspension of the vital functions and mental powers; to
   faint; -- often with away.
   [1913 Webster]

         The sucklings swoon in the streets of the city. --Lam.
                                                  ii. 11.
   [1913 Webster]

         The most in years . . . swooned first away for pain.
                                                  --Dryden.
   [1913 Webster]

         He seemed ready to swoon away in the surprise of joy.
                                                  --Tatler.
   [1913 Webster]

WordNet (r) 3.0 (2006):

swooning
    adj 1: weak and likely to lose consciousness; "suddenly felt
           faint from the pain"; "was sick and faint from hunger";
           "felt light in the head"; "a swooning fit"; "light-headed
           with wine"; "light-headed from lack of sleep" [syn:
           faint, light, swooning, light-headed,
           lightheaded]