Half of us want to be smart (5)
I believe the answer is:
swish
'be smart' is the definition.
(I've seen this before)
'half of us want' is the wordplay.
'half of' means to take half the letters.
'want' becomes 'wish' (wishing is a kind of wanting).
'us' halved is 's'.
's'+'wish'='SWISH'
'to' is the link.
(Other definitions for swish that I've seen before include "Elegant" , "Classy" , "Stylish (sl.)" , "Smart; stylish" , "Sound of cane" .)