Head start I'd concealed (3)
I believe the answer is:
hid
'concealed' is the definition.
('hide' can be a synonym of 'conceal')
'head start i'd' is the wordplay.
'start' suggests taking the first letters.
The initial letter of 'head' is 'h'.
'h'+'id'='HID'
(Other definitions for hid that I've seen before include "Concealed in orchids" , "Kept out of sight" , "wanted to be sought?" , "Remained out of sight" , "Stayed out of sight" .)