UK (London) slang for upper-end Chinese marijuana rolled in a joint. The term was popularised by UK rapper Dizzee Rascal in his song 'Stand up Tall.' The reason the word 'zoot' is used is because the joint is 'coned' or wider at one end. The marijuana is a considerably strong type.
'Never had the desire for Chinese Zoots' - Dizzee Rascal