Stupid to have insects turning up in timber centre? (8)
I believe the answer is:
imbecile
'stupid' is the definition.
(I've seen this before)
'insects turning up in timber centre?' is the wordplay.
'insects' becomes 'lice' (louse is a kind of insect).
'turning up' is a reversal indicator.
'in' means one lot of letters goes inside another.
'centre?' means to look at the middle letters (I've seen 'centre' mean this).
The middle letters of 'timber' are 'imbe'.
'lice' backwards is 'ecil'.
'ecil' inserted into 'imbe' is 'IMBECILE'.
'to have' acts as a link.
(Other definitions for imbecile that I've seen before include "A mentally deficient or stupid person" , "fool" , "Moron or cretin" , "Numbskull" , "Silly person or idiot" .)