When something fluctuates, its changes in an irregular manner, making it hard to predict that which is fluctuating. That this is the case in our sentence is hinted by the fact that the “volatility was too great” for any kind of forecasting. The word is derived from the Latin verb for “to flow,” and has related English words like “flux” and “influx” as well as “influence” and “fluid.”

The implication in this sentence is that the house was in more disrepair than even many other deteriorating houses in town. The best word to match this sense is “dilapidated,” which means “falling apart due to age or lack of care.” It is derived from the prefix “di-” meaning “apart or down from” and the Latin word for stone, “lapis.” The stone lapis lazuli is so named because it is the stone (lapis) from the place in Persia (now Iran) that was Latinized as Lazulus.

The sense of the sentence is that Luca had many formidable difficulties in his life. If something is particularly difficult in this manner, it is called “redoubtable.” The word does not mean “to doubt again.” Instead, the “re-” prefix here is an intensifier, meaning that the word literally means something like “really doubtable” (because it is so difficult).

The key is that these persons often perform actions with both hands, which is precisely what being “ambidextrous” means. Literally, it means, both (are) right or both hands are as good as right hands.

Since the children confuse the lamplight with that of a ghost, it is best described as being “spectral.” Other options like “eerie,” “devilish,” and “wicked” are not as directly related to the “ghostly” appearance. The word is related to a number of other words related to the Latin for look, such as “speculate” and “spectator,” though here the word explicitly means to have a ghostly appearance.

Since Regina is said to be looking for someone to fill the role of a mother in her life, we can say most assuredly that she is looking for a replacement mother. Whether or not she desires one who is friendly, we cannot say, and while likely she wants a devoted mother, still the sentence most directly is talking about this need for a replacement. A “surrogate” is a substitute for some position or role. It comes from the Latin word meaning to replace or depute, more distantly being derived from the combination of “super,” meaning over and “rogare,” meaning to ask. The latter is related to English words like “interrogate” and “derogatory.”

When a person has a deep psychological reliance on another person, it can often be called codependence. This is particularly the case when the other partner needs such a relationship as well, perhaps for other reasons. For instance, one person might need a mother figure and rely on some woman in his or her life, while that maternal figure might likewise have some need for someone to support her (e.g.) alcoholism. If the other person is a drinking partner, this relationship could be considered particularly codependent.

A “filial” quality is one that is due from a child. It is derived from the Latin words for daughter (filia) and son (filius).

The key expressions are “even though she did not meet the perfection.” To be “below” a level of perfection is to be “suboptimal,” a word literally meaning below the best. The prefix “sub-” has many derivatives in English (“submarine,” “substance,” and so forth). The word “optimal” (found in English words like “optimum”) is derived from the Latin “optimus,” meaning “best.”

To have great knowledge is to be “erudite,” a word whose roots indicate being taken from (e- / ex-) the state of rudeness or from being untrained (rudis). You can see the latter portion in words like “rude,” “rudimentary”, and “rudiment.”