Correct spelling for the English word "send offed" is [sˈɛnd ˈɒft], [sˈɛnd ˈɒft], [s_ˈɛ_n_d ˈɒ_f_t] (IPA phonetic alphabet).
The term "send offed" does not have an established etymology because it is not a recognized word in standard English. It appears to be a verb phrase derived from the verb "send off" and some past tense or past participle form. "Send off" means to dispatch someone or something, usually to another place or on a journey. However, the term "send offed" does not follow any known grammatical rules or patterns, and it is not listed in reputable dictionaries. It may be a nonstandard or colloquial usage specific to a certain dialect or region.