Insects circling a taut, empty web (7)
I believe the answer is:
lattice
'web' is the definition.
(thesaurus)
'insects circling a taut empty' is the wordplay.
'insects' becomes 'lice' (louse is a kind of insect**).
'circling' means one lot of letters goes inside another (circling can mean going around or containing).
'empty' means to remove the middle letters.
'taut' with its middle removed is 'tt'.
'a'+'tt'='att'
'lice' placed around 'att' is 'LATTICE'.
(Other definitions for lattice that I've seen before include "Trellis: maybe" , "Arrangement with bars" , "Network of crossed bars" , "Framework for window" , "Crystalline structure" .)