Words related to -ment
1520s, "request, requisition" (a sense now obsolete), from require + -ment. Meaning "things required, a need, something necessary" is from 1660s. Meaning "that which must be accomplished, necessary condition" is by 1841. Related: Requirements. Fowler points out that requirement "means properly a need" and requisite "a needed thing," though the distinction is a fine one.
That which is required by the nature of the case, or is only indirectly thought of as required by a person, is called a requisite ; that which is viewed as required directly by a person or persons is called a requirement ...; a requisite is more often material than a requirement ; a requisite may be a possession or something that may be viewed as a possession, but a requirement is a thing to be done or learned. [Century Dictionary, 1895]
1590s, "act of retreating, act of falling back," also "act of withdrawing into seclusion," from French retirement (1570s); see retire + -ment. Meaning "privacy, state of being withdrawn from society" is from c. 1600; that of "withdrawal from occupation or business" is from 1640s.
Solitude is the condition of being absolutely alone, whether or not one has been with others, or desires to escape from them .... Retirement is comparative solitude, produced by retiring, voluntarily or otherwise, from contact which one has had with others. Seclusion is stronger than retirement, implying the shutting out of others from access .... [Century Dictionary]
1580s in the military sense of "interior defensive works;" see retrench (v.1) + -ment. In the sense of "action of lopping off or pruning" it is attested from c. 1600, from obsolete French retrenchement "a cutting off or out," from retrencher, later retrancher (see retrench (v.2)). The sense of "act of economizing" is from 1660s.