Green’s Dictionary of Slang

1. a wander or walk around.

1960		in Sat. Eve. Post 24 Dec. 81: Go take a mosey around the place, Joe [HDAS].
1983		A. Payne ‘Willesden Suite’ Minder [TV script] 28: Going to have a mosey round.
1998		K. Sampson Awaydays 10: Marty and Eddie want to stay on until Wrexham central and have a good mosie around the town.
2004		D. Willet et al. Lonely Planet Greece 593/1: [The Archaeological Museum]’s worth a mosey around.

2. a look.

2001

K. Sampson Outlaws (ms.) 3: Flipper and that coming up to have a mosey at the pondlife in the Britannia.