Sanskrit terms in English

very old words

ginger
शृङ्गवेर (śṛṅgavera) [English from Latin zingiberi from Late Greek ζιγγίβερις (zingíberis)]
pepper
पिप्पलि (pippali) [English via Latin. But this may be common Indo-European]

greeting

namaste
नमस्ते (namaste)

religion

Hindu
हिंदु [derived from Sanskrit; not properly a word]
Hare Krishna
हरे कृष्ण (hare Kṛṣṇa)
Buddha
बुद्ध (buddha)
Jain
जैन (jain)
deva: god
देव (deva)
devi: goddess, deity
देवी (devī)
veda
वेदा (vedā)
tantra
तन्त्र (tantra)
boddhisatva
बोधिसत्त्व (bodhisattva)

religious concepts

karma
कर्म (karma)
dharma
धर्म (dharma)
nirvana
निर्वाण (nirvāna)

deities

Brahma
ब्रह्मा (Bramhā)
Sarasvati
सरस्वती (Sarasvatī)
Vishnu
विष्णु (Vishṇu)
Lakshmi
लक्ष्मी (Lakshmī)
Shiva
शिव (Shiva)
Kali
काळी (Kālī)
Rama
राम (Rāma)
Krishna
कृष्ण (Kṛṣṇa)
Ganesh
गणेश (Gaṇesha)

vedic literature

mantra
मन्त्र (mantra)
mandala
मण्डल (maṇḍala)
om
ॐ (aum)

relating to yoga

yoga, yogi
योग, योगी (yoga, yogī)
guru
गुरु (guru)
swami
स्वामी (swāmi)
tantra
तन्त्र (tantra)
hatha
हठ (hatha)
chakra
चक्र (chakra)

other

raga
राग (rāga)
swastika
स्वस्तिक (svastika)