Giddy, dizzy, vertiginous, swimming, dazzled are comparable when meaning affected by or producing a sensation of being whirled about or around and consequently confused.
Giddy and dizzy are often used interchangeably with one another but giddy is sometimes preferred for stressing the mental confusion which results and dizzy for emphasizing the physical quality of the sensation.
Both giddy and dizzy are also used in an extended sense implying a lack of balance in persons or in things and, usually, an undue lack of steadiness or seriousness.
Vertiginous retains in its extended uses much of the connotation implicit in its basic relation to vertigo ; it may come close to dizzy in its suggestion of lack of steadfastness and constancy or may attribute a dizzying effect to the thing qualified or it may stress a confusing effect like that of vertigo.
Swimming is applied especially to the head, brain, or eyes of a person suffering from dizziness; when so used, it suggests the physical sensations of swift, unimpeded, yet uncontrollable movement.
Dazzled applies to the physical, mental, or spiritual vision when overpowered and confused by or as if by a blinding light; it connotes, therefore, an effect suggestive of dizziness but without the sensation of being about to fall.