needs = los necesidades
The question is a bit ambiguous, needs greater clarification to be answered. For example, if you mean 'the F*** word', it would in any case be 'the J****' word in Spanish. But what you intend by 'the F word' is no clearer than possibly 'the J word' is to you....
El tiempo. This also means "time", so it needs context to be understood.
The spanish word for guitar is Guitarra. This English word came directly from the Spanish word, but it is not a Spanish word any more than the Spanish word is an Arabic word. "qutar" or a Greek word Chirara.
One combination of these letters that makes sense is "arte". There may be others.
The spanish word for did is hizo.
"De" is the Spanish word for "of".
The Spanish word for "in" is "en".
"Con" is the spanish word for "with".
The Spanish word for "who" is "quién".
The Spanish word for "she" is "ella".
The spanish word for leg is Pierna. :]
According to the Royal Spanish Academy, there is no such word in spanish.