secret - latent - occult - covert - ulterior - privy
all synonyms..
The answer is synonyms.
Synonyms for alternate are, different, varied.
There are lots of synonyms to "in addition". Some of these synonyms are: added, additional, ancillary, another, more, plus, supplemental and supplementary.
Beside, adjacent to, alongside, are three choices for synonyms of "next to".
Two synonyms for the word 'strong' are 'tough' and 'capable'