absolutely essential; indispensable; vital; critical
lack; absence; shortage; deficiency; privation
oxygen deficiency; oxygen shortage; lack of oxygen
flawless; absolute perfection
deficiency; insufficiency; shortage; lack; want; dearth
filling a vacancy; supplementation; substitute; deputy; alternate
having no money; lack of money
vacant position; vacancy; opening; unfilled position
lack; deficiency; vacancy; absence; non-attendance
deficiency disease (e.g. protein, vitamin, etc.)
absence due to illness; sick leave
attendance; presence and absence; attendance and non-attendance
oxygen deficiency; anoxia; hypoxia
to take a roll call; to take the register
feeling that something is missing; sense that something is incomplete
special election; by-election; bye-election
authorized absence; permission of absence from class(es)
provisional admission; waitlisted acceptance; conditional acceptance
running out of gasoline (petrol)
failure to pay one's compliments; omission of courtesy
intermittence; intermittent
iron-deficiency anemia; iron-deficiency anaemia
removal; omission; lusting
attention deficit hyperactivity disorder; ADHD
vitamin deficiency disease; avitaminosis; hypovitaminosis
omission of a character; omitted character; blank type; insertion of blank spaces before and after the names of dignitaries (as a sign of respect)
fragment (e.g. of works); incomplete set; incomplete state
spare player; substitute; sub; benchwarmer
to bridge a gap; to supply a lack
flawless; perfect; (a nation) having never been invaded by outside forces
running out of electricity (esp. an electric vehicle); having an empty battery
missing issue (of magazine)
refraining from offering the (New Year's) greetings during the period of mourning
essential fatty acid; EFA
disappointment; disillusion; resentment
piece of writing with a missing part; missing part (sentence, passage, etc.); lacuna
intermittent river; intermittent stream
intermittent explosive disorder; IED
intermittent explosive disorder; IED
absence for personal reasons
attention deficit disorder; ADD
attention deficit hyperactivity disorder; ADHD
attention deficit hyperactivity disorder; ADHD
callousness (disregard for the suffering of others)
hypoxic state; oxygen-deficient state