Cuindlis is an Old Irish (Gaelic) name meaning, (as far as can be determined) "head of the enclosure". This could mean, more loosely, anything from "master of the cattle pen" (i.e. rancher or dairy farmer), to perhaps even "master of the fort", depending on just what sort of enclosure was meant.
The original form of the name came in several variants, including at least these three: Cuindlis, Cuindilis, and Cuindleas. Today, after the anglicization and later modifications of Gaelic names, there are many family names descended from Cuindlis. The two most-frequent variants are McCandless and McCandlish, with many sub-variants like Chandlish, McCandliss, McAndless, and McCanles. Quinlisk (or O'Quinlisk) represents a less common (and probably more widely-separated) branch, with its own sub-variants like Quinlish and Quinlos. Most of the other variations appear to be directly descended from M[a]cCandlish and M[a]cCandless. K-spelled variants like MacKanles, etc., have also occurred, but appear to be largely if not entirely extinct.
The -ish spelling may be older, but is less numerous than -ess. The -ish version is mostly Scottish, -ess mostly Irish, though with a great deal of overlap in both directions. Quinlish, which appears to be exclusively Irish, is actually closer to the original pronunciation of the Cuindlis spelling, and may be the oldest. The Cuind[i]lis spellings ended with a "sh" sound, probably giving rise to both the Quinlish and McCandlish and similar versions, while Cuindleas ended with a "s" sound, probably giving rise to McCandless and its sub-variants. Notably, however, the spellings have been widely regarded as synonymous many times, with genealogies showing a McAndlish who's son goes by McCandless and who's daughter in turn is a McCandlish, for example. This "bleed-over" does not appear to occur between the [O']Quinlisk/[O']Quinlish versions and the [M[a]c]Candless/[M[a]c]Candlish variants.
It is unknown at present whether or not all of the Cuindlis/Cuindleas-derived names are in fact directly related. It is entirely possible that more than one person bearing this name as his given name gave rise to patronymic family names (either different ones, e.g. McCandlish and McCandless coming from a different ancestory, or even multiple instances of the exact same spelling.)
Some of the more common name variants:
[M[a]c]An[d]lish
[M[a]c]An[d]les[s]
[M[a]c]An[d]lis[s]
[M[a]c]Can[d]lish
[M[a]c]Can[d]les[s]
[M[a]c]Can[d]lis[s]
[M[a]c]Can[d]las[s]
[M[a]c]Can[d]los
[M[a]c]Can[d]leis
Chan[d]lish
Chan[d]less
[O']Quinlisk
[O']Quinlish
At this point, there is not even a family association. The family (or, rather, a particular but nebulous and hard to pinpoint Scottish branch of it) is regarded by some as an unofficial sept of Clan MacGregor, and has ties with the MacGregors, Buchanans and possibly the MacArthur Campbells (who trace their lineage to King Arthur himself), ca. late 1600s - early 1700s (the time of Rob Roy), possibly earlier. A MacGregor family historian contacted recently was unable to find any records of such links, other than some marriages (e.g. a McCandlish who married a MacGregor was the Clan Gregor Society treasurer for several decades).
Other family branches report an association with the Gordon clan, but documentation is again lacking, as of this writing.
Despite lack of a clan, there is a McCandlish/McCandless tartan. Like most family and clan tartans it dates to recent times, though more recent than most.
Several McCandlishes, M'Caunlesses, Mac Candlesses, etc., were armigerous (i.e. had royally-granted coats of arms) - at least 5 crests are known.
Please note that these are not "family" crests or coats of arms. Such honors, despite what heraldic product mongers in the US will tell you, belong to specific individuals, and are inherited; they do not belong to entire families, though it is permissible under Scottish heraldry law to devise clan or family "badges" (sometimes incorrectly called "crests") based on (but "differenced", with a surrounding belt and buckle, from) an individual's crest. This is usually if not exclusively done with the crest of the clan chief, and the present author does not know if it is permissible to do this with any known crest held by a member of the family, in the absence of a recognized chief.
Central Ireland -> Scotland; later from cen. Ireland to US, Canada,
Australia, New Zealand, England
Scotland -> US, Canada, Australia, NZ, England, and N. Ireland
N. Ireland -> US, Canada, Australia, NZ, England, and back to Scotland
again
Scotland -> US, Canada Australia, NZ, England
plus many instances of migration between the colonies (e.g. Canada -> NZ,
Aus. -> US).
There was a lot of jumping back and forth across the Irish Sea. The family must be regarded, one supposes, as thoroughly Scots-Irish, rather than either one or the other.
Besides the real thing, several fictional McCandlesses and similar have
made appearances in novels, on tv, and on the big screen..