Milquetoast
baby
big baby
chicken
crybaby
doormat
dull tool
gutless wonder
invertebrate
jellyfish
lightweight
meek soul
milksop
mollycoddle
namby-pamby
nebbish
nonentity
pansy
pantywaist
pushover
sad sack
sissy
softling
sop
weak sister
weakling
wuss
eclecticism
evildoer
flautist
lookers-on
manhole
playgoer
pocketknife
saunterer
shirker
stammering
telegraph-operator
tossers
trifler
waster