Green’s Dictionary of Slang

garm n.

[abbr. SE garment]

(UK black) usu. in pl., clothes, clothing.

[UK]N. Barlay Curvy Lovebox 60: Your garms are wicked.
[UK](con. 1981) A. Wheatle East of Acre Lane 68: I t’ought you wanted to buy some garms for de wedding?
[UK]G. Malkani Londonstani (2007) 4: His perfectly groomed garms that made it look like he went shopping with P Diddy.
[UK]A. Wheatle Crongton Knights 10: There they were, Mum’s nice blouses and skirts alongside his own garms.
[UK]G. Krauze What They Was 26: Garms in the cupboards.

In phrases

garm up (v.)

(UK/W.I.) to dress oneself up.

[UK]N. Barlay Curvy Lovebox 141: Steffi’s garmed up for a disco inferno.
[UK]N. Barlay Hooky Gear 31: I know we got as many hours as it take Libby to garm up and steam down.