Look to have half of school holding attention (6)
I believe the answer is:
search
'look' is the definition.
(synonyms)
'half of school holding attention' is the wordplay.
'half of' means to take half the letters.
'holding' means one lot of letters goes inside another.
'attention' becomes 'ear' (having someone's ear is having their attention).
'school' with half the letters taken is 'sch'.
'sch' going around 'ear' is 'SEARCH'.
'to have' acts as a link.
(Other definitions for search that I've seen before include "Frisk" , "Try to find something by looking" , "Showing pleasure" , "Look carefully (for)" , "Scour, seek" .)