The Spanish language was enormously influenced by Arabic dialects during the age of moorish rule in the Iberian peninsula. But since culture usually goes both ways I wanted to know if Arabic was also influenced by Spanish, and to what degree.
Arabic is spoken over a wide area, from Morocco to Oman, and comprises a large number of dialects that are not all easily mutually-intelligible. Spain exerted relevant influence as a colonial power mainly in the area of Spanish Morocco, and Moroccan Arabic is the only variety of Arabic with any appreciable number of Spanish loans. The influence of Arabic on medieval Castilian was much greater, which resulted in modern Spanish, as was the influence of French on Moroccan Arabic.
It should be noted that both directions of influence were limited to lexical loans, and not syntactic ones. There is one defunct (non-productive) morphological loan in Spanish of Arabic origin that I know of, which is a derivational suffix for adjectives.
People in moorish Spain would speak Arabic or Mozarabic depending on the area, Mozarabic referring not to one language, but to a continuum of arabicized Latin dialects. The current theory is when use of Castilian expanded into the region it took on many of the Arabic roots in use in the local language, rather than having direct influence from Arabic speakers.
So most Arabic dialects (or languages if you like, there is no difference), or let's say most of the Arabic dialect continuum lacks the Spanish loans Moroccan has. And of course standardized Arabic, such as MSA used as a medialect throughout the Arab world, or Korannic Arabic which has liturgical use, have not been influenced by Spanish at all.
The existence of Spanish loans in Moroccan Arabic is not due to interaction between Arabic and Mozarabic speakers in moorish Spain, but rather more recent colonialism and after that, trade.