to cover up; to conceal; to close (a door, book etc); (coll.) to get (one's fingers etc) caught when closing a door or lid; (literary) to launch a surprise attack

to be secretive; to try to cover up (idiom)

to partially obscure; (of a door, gate or window) slightly open; ajar; not fully shut; unlocked; (of a jacket or shirt) unbuttoned

counter soldiers with arms, water with an earth weir (idiom); different situations call for different action; to adopt measures appropriate to the actual situation