As defined by Merriam-Webster's online dictionary, Wicca is a religion. To be more precise, maybe, it is a nature-based religion & thus, more a way of life, not unlike Christianity in that respect. Unlike Christianity, though, Wicca honors the female aspect of the Creator, or the Divine Feminine. Wicca, as I understand it ( I could be wrong ), is not dogmatic about its beliefs, either, but rather honors the Divine in all its glorious aspects, especially Nature, which, it might be noted, is the physical manifestation of its Power. As a religion, then, Wicca falls under the umbrella of Paganism, which predates Christianity & in fact forms the foundation for much of what we know, again, traditionally speaking, as Christianity!
Although not necessarily known as such until sometime later, Paganism, as an umbrella term ( anachronistically in reverse? ), can be noted as predating Christianity. A 'pagan', in simple terms, was anyone not a Christian or Jew ( mostly the first, rather than the latter ). As such, then, 'Pagan' was a large denominator, covering everyone, from those who worshiped Nature itself to those who, like Christians, worshiped a God or gods who were petty & must be appeased through sacrifice ( human or animal )!
Modern Paganism, which is also an umbrella-term ( including Wicca ), is a throwback to the Ancient Ways, the Old Ways of understanding what ( or Who? ) made the world go round. Ranging from those who worshiped a single entity ( monotheistic ) to those who worshiped a multiplicity of gods ( polytheistic ), Paganism, from culture to culture, revealed a people's perception ( only ) of who & what 'God' was. As we've noted previously, every culture known to man ( kind ) had their own version of a creation story, all of which are similar yet dissimilar. Culturally speaking, these stories are all pieces of the same puzzle, a grasping for 'God' that has gone on for Time Immemorial!
In our English Bibles, we read about the error of those who worshiped 'the creature rather than the Creator' ( Romans 1:25 );: while it must be noted here that the Christian Scriptures are the Story of Israel, not humanity per se, this passage has been applied, in the widest sense, to any who do not acknowledge the Christian or Jewish God. While there may be some value to this consideration, it should be understood that, while there is a Supreme Being, an Intelligent Designer, if you will ( the All ), there are many aspects to the Divinity, most if not all of which are manifest in the Creation.
To worship something, again, in simple terms, is to ascribe worth to a particular object. That object may be another person that we hold in high esteem or simply an idea, true or false, that one holds ( especially referring to Deity ). Thus the Nature Worship of Wicca & Paganism, in those terms, sounds a bit different than worshiping 'the creature rather than the Creator', does it not? Now, admittedly, there are those of both 'camps' ( although the same could almost be said of certain forms of Christianity ) who are guilty of this, but this by no means implies that Paganism as a whole idolizes what is created, rather than ascribing worth to the One True God, the Source of All that Is.
Wicca, being associated with the sadly misunderstood terms, 'witch' & 'witchcraft', naturally enjoys ( just a BIT of sarcasm there ) the stigma normally attached ( in the Christian 'camp', anyway ) to those terms. 'Witches', contrary to popular opinion ( and you probably won't find anything near this definition in any but the oldest dictionary, if at all ), depending, of course, on the person, CAN be evil ( or rather, DO evil-using their Power wrongly, whether purposely or ignorantly ), are simply those who have learned how to tap into their own inner resources as well as utilizing what Nature has provided. As another religion, one might note that Wicca, along with other forms of Paganism, is simply another way to use our innate creativity & to explain the Nature of it all: as a way of life, Wicca requires simply that one live in harmony with his or her surroundings & that they respect the Divinity in All its many forms!
Charles Haddon Shank