Resource, resort, expedient, shift, makeshift, stopgap, substitute, surrogate can all denote something to which one turns for help or assistance in difficulty or need when the usual means, instrument, or source of supply fails one, is not at hand, or is unknown to one.
Resource applies to an action, activity, person, method, device, or contrivance upon which one falls back when in need of support, assistance, or diversion.
Resort is less often used than resource except when qualified by last or in the phrase “to have resort to”.
Expedient applies to a means, device, or contrivance which serves in place of what is usual or ordinary, or sometimes as a means, a device, or a contrivance to accomplish a difficult end easily or without waste of time.
A shift is commonly a tentative or temporary and often imperfect expedient; the term when applied to plans or stratagems typically implies evasiveness or trickery.
Makeshift is even more derogatory than shift for it implies substitution of the inferior for the superior and often it imputes carelessness, indifference, or laziness to the one who chooses or makes use of it.
Stopgap applies to a person or thing that momentarily or temporarily supplies an urgent need or fills a gap, hole, or vacancy.
Substitute (see also SUBSTITUTE 2 ) does not carry as strong a suggestion of an emergency or exigency as the preceding terms do; the word is applicable to something one chooses, accepts, or prefers, whether rightly or wrongly, rationally or irrationally, in place of the usual or original thing, or which has been invented or devised to take its place or to do its work.
Surrogate is a somewhat learned word for a substitute. It is frequently applied to people whether as literal replacements or as replacement figures in psychological or sociological analyses.