No, because sick is an adjective and there are not plural forms for adjectives. However, if you changed it into a noun (i.e., sickness) then you could make it into sicknesses.
Some compound words that contain the word sick are:
airsickcarsickheartsickhomesicklovesicksickbaysickoutsickroom
Seasick.
No, building is not a compound word.
άρρωστος the word sick
The contraction (not a compound word) is doesn't.
Upwards is a compound word.
There is no compound word.A compound word is a word like bus-stop.Husban is spelt like this husband
Upstairs is a compound word, so it is one word.
The word sick is an adjective (sick, sicker, sickest), a word that describes a noun; sick is also a noun (a non-count noun) for a group that are sick, for example 'caring for the sick'.
It cannot be a compound word.
Mango is not a compound word.
The compound word with "shield" in it is "shieldmaiden."