expression
no filter; without processing
Commonly used as a hashtag on social media to indicate a photo has not been edited or filtered. The literal meaning is 'without processing'.
この写真は加工なしです。
This photo has no filter.
加工なしの自然な肌を見せたい。
I want to show my natural skin without processing.
Similar meaning 'unprocessed' or 'no filter', but 無加工 is a noun/adjectival noun, while 加工なし is a phrase.
Compound of 加工 (processing) + なし (without). A straightforward modern phrase.