Having worked with many people from India and Pakistan in the 1990s, I was often fascinated by words that sounded Arabic in origin. When asking about the meaning, they were indeed Arabic. And I could detect more words in the few Hindi Bollywood movies that I have seen as well.
Arabic influence on Hindi may have been via several avenues. One was via Farsi (Persian) as an intermediate, having been the language of the court for the Mughal emperors. Another was through Muslim scholars using these words from Arabic texts and they made their way into the vernacular.
Whatever the avenues are, here are some words that I did recognize, with the Arabic spelling and Arabic meaning, which the Hindi derives from, but may deviate somewhat from.
waqt = وقت = time
admi = آدمي = human being
leken = لكن = but
shaitan = شيطان = devil, satan
mabhoom = مبهوم = hidden, unknown future event
shukriya = شكر = thank you, not an exact copy, "ya" is added
khabar = خبر = news item
akhbar = اخبار = plural of above
ajab = عجب = wonder, strange occurrence
ajib = عجيب = strange, derived from above root
ajaib = عجايب = plural of ajab, same root. Punjabi/Sikh name
aql = عقل = mind, intellect
azam = عظم = great
azmat = عظمة = greatness, derived from above root
silsila = سلسلة = chain, Hindi = series of events
mushkil = مشكل = problem, unclear
hal = حال = condition, state
mahabat = محبة = love
kharab = خراب = destruction
bilkol = بالكل = "all of it", derives from كل
ya3ni = يعني = which means, meaning, also a "conversation filler"
intezar = انتظار = waiting for
mohtaram = محترم = respected
mukarram = مكرم = from كرم karam, generosity
sahib = صاحب = companion, friend, used as Mister in Hindi
adab = آداب = good manners
adat = عادات = customs
aynak = عين = from eye (ain), means spectacles in Hindi
akhir = آخر = the end
alam = عالم = universe
alim = عالم = scholar, scientist, learned person
asal = أصل = origin
asali = أصلي = original
ashiq = عاشق = lover
aziz = عزيز = dear
filhal = فى الحال = currently, at the moment
marhoom = مرحوم = is often used when referring to people who have passed on not unlike allah yarhamuh. Same usage as in rural Egypt
kalam = كلام = speech, especially the words of a poet
qalam = قلم = pen
kursi = كرسي = chair
ijazat = اجازت = permission
hayat = حياة = life
There are also words that are what language teachers call "false friends" :
gharib (غريب), for example, usually means poor and not "strange, foreign" though it can also mean the latter in certain contexts, e.g. عجيب و غريب.
This is not unlike in the Middle East where gharib also means "stranger, foreigner, wanderer, someone with unknown origin/domicile".
There is also a Hindi/Urdu to English dictionary which allows input in Arabic characters.
Thanks to Junaid Quadri for the additions.
If you know some more words in Hindi that are Arabic, please post them below in the comments ...