xmodmap -e "keycode 77 = NoSymbol"

"xdotool key ctrl+w"
 b:8 + Release

"xdotool key ctrl+d"
 b:9 + Release

"NoCommand"
 c:77

$ xmodmap
xmodmap:  up to 3 keys per modifier, (keycodes in parentheses):

shift       Shift_L (0x32),  Shift_R (0x3e)
lock        Caps_Lock (0x42)
control     Control_L (0x25),  Control_R (0x69)
mod1        Alt_L (0x40),  Meta_L (0xcd)
mod2        Num_Lock (0x4d)
mod3
mod4        Super_L (0x85),  Super_L (0xce),  Hyper_L (0xcf)
mod5        ISO_Level3_Shift (0x5c),  Mode_switch (0xcb)

$ xmodmap -e 'remove mod2 = Num_Lock'