Vim clear last search highlighting
To turn off highlighting until the next search:
:noh
Or turn off highlighting completely:
set nohlsearch
Or, to toggle it:
set hlsearch!
nnoremap <F3> :set hlsearch!<CR>
From the VIM Documentation
To clear the last used search pattern:
:let @/ = ""
This will not set the pattern to an empty string, because that would match everywhere. The pattern is really cleared, like when starting Vim.