Now this is total twaddle, so don't expect any great theological or other insights!

Recently in stuff I've been reading, I have come across words that seem to me to have been derived from others that are perfectly adequate to express the same concept.

In a theological paper, the word 'explicate/explicated' was used repeatedly where 'explain/explained' would have served just as well.  Is there such a word, I wondered: the web dictionary tells me there is and that 'explicate' means 'to offer a detailed explanation.'  So there must be potential for more new words for further degrees of explanation - how would you express 'the act of offering a complete explanation'?!

In a report on food safety the word 'disinfectation' was used to described cleaning surfaces.  This the web dictionary does not recognise, but what is wrong with 'disinfection'?  Is there a subtle diffenece I'm missing?  Or has English just gone a bit mad as we keep inventing new words that get longer and longer either as a stand against txt culture or because our vocabularies are not adequate for what we want to say?  I realise that language is always evolvificating (like evolving but more so!) and that Englishish is about as good as it gets, perhaps I'm just getting staid and old but I do wonder sometimes...!