GRE : Essential Latin Roots : Mal-, Ob-, Os- and Oc-

maladroit
adjective
lacking in adroitness
malapropism
noun
habit of misusing words ridiculously, esp. by the confusion of words that are similar in sound
malevolence
noun
quality, state, or feeling of being malevolent
malign
verb
speak harmful untruths about
malinger
verb
pretend illness, esp. in order to shirk one's duty, avoid work
malleable
adjective
capable of being extended or shaped by hammering or by pressure from rollers
obdurate
adjective
unmoved by persuasion, pity, or tender feelings
obfuscate
verb
confuse, bewilder, or stupefy
oblivious
adjective
unmindful
obloquy
noun
censure, blame, or abusive language aimed at a person by many
obsequious
adjective
characterized by or showing servile complaisance or deference
obstreperous
adjective
resisting control or restraint in a difficult manner
obtain
verb
come into possession of
obtrusive
adjective
having or showing a disposition to obtrude, as by imposing oneself or one's opinions on others
obtuse
adjective
not quick or alert in perception, feeling, or intellect
obviate
verb
anticipate and prevent or eliminate difficulties, disadvantages by effective measures
occluded
verb
close, shut, or stop up
ossify
verb
convert into or cause to harden like bone
ostensible
adjective
outwardly appearing as such
ostentation
noun
pretentious or conspicuous show, as of wealth or importance
ostracism
noun
exclusion, by general consent, from social acceptance, privileges, friendship