si ‧ dle /ˈsaɪdl/ BrE AmE verb [intransitive always + adverb/preposition]
[ Date: 1600-1700 ; Origin: Probably from sideling 'sideways' (14-19 centuries) ]
to walk towards something or someone slowly and quietly, as if you do not want to be noticed
sidle up/towards/along
A woman sidled up to us and asked if we wanted to buy a watch.