Where'er is a poetic contraction of "wherever" often used in romantic literature and classical poetry. There are various synonyms for this word that can be used depending on the context or tone. "Wherever", which means anywhere something can happen, is a straightforward substitute in regular writing. "In all directions" and "everywhere" are also viable synonyms for this word. "Wheresoever" and "whithersoever" are old-fashioned alternatives that can add literary flair to your writing. "Anywhere" and "everyplace" are casual options, while "anyplace" and "everywhere" can be seen as colloquial. Ultimately, the correct synonym depends on the intended tone of the sentence and surrounding context.