Look untidy if thus (6)
I believe the answer is:
shufti
'look' is the definition.
(a quick or furtive look)
'untidy if thus' is the wordplay.
'untidy' indicates anagramming the letters.
'if'+'thus'='ifthus'
'ifthus' is an anagram of 'SHUFTI'.
(Other definitions for shufti that I've seen before include "Glance (colloq.)" , "Colloquial word for look" , "Quick look (colloq.)" , "Look (inf. from the Arabic)" , "Informally, a brief inspection or look" .)