These words refer to a lack of yield or value or to the inability to have children. Sterile functions in all these senses: sterile soil; a sterile discussion; determining whether it was the husband or wife who was sterile. Barren is the only other word here that applies to all three situations, but it is less technical-sounding and more dramatic than sterile : the barren desert; a debate that was barren of results; a barren woman. In the last sense, the word has an older, more Biblical ring and applies to women (or the union itself) rather than to men. Also, the word is less often used than sterile since it may seem critical rather than factual. Sterile itself, too can seem harsh to some for it can carry overtones of clinical usage meaning devoid of all organisms. This may be one reason why infertile is often substituted for it, although infertile may refer to the simple lack of success at having children for any reason, without necessarily implying that either the man or woman is biologically sterile . The word is used also in the agricultural sense, although its increasing use in reference to child-bearing may have diminished its usefulness here: topsoil rendered infertile by excess alkalinity. Childless is the only word here that refers exclusively to people whose sexual union does not result in offspring. It points to the simple fact of this lack, whether it comes about involuntarily or by choice: a childless couple; deciding to remain childless for the first few years of marriage; the adoption of children by those who are childless themselves.

The remaining words have no reference to child-bearing, but do refer to other senses grouped here. Arid most concretely indicates a lack of yield because of excessive dryness or heat: miles of arid sand dunes; an arid climate. In terms of values, the word suggests dullness or lack of results: an arid play; a government arid of new approaches. Unfruitful and unproductive are closely allied; both can apply to a lack either of yield or of value. Unfruitful would seem more open to the former, unproductive to the latter: an unfruitful use of land; an unfruitful season; mediation that was unproductive of changes on either side. This neat pattern is far from being the case in actual usage: unfruitful summit conferences; unproductive stretches of swamp land. In any case, unfruitful tends to sound more dramatic or colourful, and need not suggest something totally barren of yield or value: This soil is relatively unfruitful without the use of fertilizers. Unproductive gives a more factual tone and tends to suggest a more nearly complete lack of any result whatever: hampered by an unproductive search for tell-tale clues.