tard- +

(Latin: slow; sluggish)

Ad vindictam tardus, ad beneficientiam velox. (Latin)
Translation: "Punish slowly, do good quickly."

Motto of Henry I (918-936) who forced the dukes of Bavaria and Swabia to recognize his authority. He protected Saxony against the Slavs by building several fortresses and by creating a powerful cavalry which he used to defeat the invading Magyars on the Unstrut River in 933.

King Henry succeeded in annexing the key Carolingian realm of Lorraine to the east Franconian realm. He is regarded as the actual founder of the German Empire.

aquitard
1. A leaky confining bed that transmits water at a very slow rate to or from an adjacent aquifer.
2. A geologic formation that may contain ground water but is incapable of transferring that water to the surface.
3. A bed of low permeability adjacent to an aquifer.

An aquitard may serve as a storage unit for groundwater, although it does not yield water readily.

mental retardation
Intellectual functioning that is significantly below average and is associated with impairment in social adjustment, manifested prior to maturity; usually early in life.

The term is specifically defined in different nations and by some professional organizations, but no single definition is accepted worldwide.

psychomotor retardation
Delay in the attainment of motor skills, language development, and social responsiveness in infancy and childhood.

A marked discordance between the degree of motor retardation and that of social response and alertness, as revealed by testing, may predict either cerebral palsy or a primary intellectual impairment.

psychosocial retardation
Mental retardation due to, or exaggerated by, cultural, social, and interpersonal inadequacies in the person's environment.
retard
1. To make slow; delay the development or progress of (an action, process, etc.); to hinder or to impede.
2. A slowing down, diminution, or hindrance, as in a machine.
3. To cause to move more slowly or to operate at a slower rate: "This medication could retard your heart rate."
4. To slow the growth or development of something: "The brain damage may retard your child's language development."
5. To lose velocity; to move more slowly.
6. Slang: a reference to a person of subnormal intelligence or someone who is considered to be foolish or socially inept.
retardate
A mentally retarded, or mentally defective, person.
retardation
1. Delay; hindrance; delayed development.
2. The process or fact of slowing down.
3. Something that acts as a delay or obstacle to progress.
4. The extent to which something is held back or delayed.
5. Sometimes a reference to the lack of normal development of intellectual capabilities.
retarded depression
1. A state of clinical depression in which the individual is lethargic and slow to initiate action.
2. A major depressive disorder with psychomotor retardation which is a generalized slowing of physical and emotional reaction; such as, that seen in a major depression and in catatonic schizophrenia.
retarder
1. An agent used to slow the chemical hardening of gypsum, resins, or impression materials used in dentistry.
2. Any substance added to rubber to delay or to prevent vulcanization.
3. Any substance added to delay a process of anything.
tardamente
Slowly, a musical direction
tarde venientibus ossa
For latecomers, the bones.
tardigrade
Moving slowly; a reference to sloths.
tardigradous
Moving slowly; slow-paced; moving or stepping slowly.
tardiloquent, tardiloquence, tardiloquy
1. Speaking slowly; slow speech.
2. Talking in a slow way or drawing one’s speech out at length.

Cross references directly, or partly, involving "slow, slowness, slow of, sluggish": dys-; lent-.