Master Spy
Romanoff is a dangerous secret agent highly skilled in espionage, stealth, disguise, infiltration, and demolitions. Her talents and years of experience have enable her to reach a high ranking as a special agent of S.H.I.E.L.D. Romanoff is well versed in internal destabilziation and was soon deemed a threat to global security because of this. Romanoff's skills are so legendary that Nick Fury created a Lie Detector that he hoped she could not deceive.
Master Martial Artist
Romanoff is one of the best fighters in the world, having been trained from a young age in the Red Room and S.H.I.E.L.D. in her later life as a top operative. During her time in the Red Room, she was seen using her martial arts to defeat a grown man by swinging his head into the corner of a desk, proving how formidable she was even when she was young. She is extremely skilled in the field of martial arts, having mastered arts such as sambo, lucha-libre style wrestling, parkour, krav maga, hapkido, multiple styles of kung fu, taekwondo, and kali with her batons. Romanoff has efficiently taken down many enemies, such as multiple Hammer Industries security guards, Georges Batroc's armed pirates, several members of STRIKE, Ultron Sentries, and even Chitauri aliens. She is skilled enough to be able to defeat a mind-controlled Hawkeye, maintain the upper hand against Ant-Man, and even hold her own against the much stronger Winter Soldier, though he was able to bring her down in the end. Black Widow also proved capable of defeating numerous Outriders and managed to compete with Proxima Midnight alongside Okoye, even managing to disarm her with her baton, holding her off long enough for Wanda to kill her. In addition, she had enough skill to stab Corvus Glaive using Proxima Midnight's Spear.
Master Acrobat
Romanoff is highly skilled in incorporating gymnastics and acrobatics into her fighting style as she battles opponents. During her fight within Hammer Industries Headquarters, Romanoff used these skills to defeat the guards. During the Chitauri Invasion, she got to ride a Chitauri Chariot by using her acrobatics to commandeer it.
Master Assassin
Romanoff is notorious in the art of assassination, considered to be one of the most dangerous assassins in the world. She is known to have killed many people during her time serving the KGB and S.H.I.E.L.D.. During her time in the Red Room, Romanoff was trained to kill without remorse and was seen demonstrating her sharpshooting skills on a live captive, showing no emotion as she killed him.
Master Marksman
Romanoff is a very accurate marksman skilled in sharpshooting. During the Battle of Washington, D.C., Romanoff would have shot the Winter Soldier through his eye if he had not been wearing his protective goggles. She had also been trained from a young age in the art of sharpshooting, as she was seen practicing on targets, making several headshots in quick succession.
Multilingualism
Romanoff is fluent in Latin, Russian, English, French, German, Chinese, Italian, and various other languages.
Gifted Intellect
Romanoff's intellect seemingly puts her on par with Steve Rogers and Clint Barton. She possesses the ability to quickly process multiple information streams (e.g., threat assessment) and rapidly respond to changing tactical situations. Romanoff also possesses a vast knowledge of human anatomy, displayed by her often using joint locks and hitting enemies in the weakest parts of their bodies; for example the crotch, stomach, armpits, and the head. Her prodigious skill from her years of training also allow her to predict her opponents' plans of attack as well, such as when she was able to save herself, Captain America, and Falcon from being shot by the Winter Soldier by predicting the order in which he would shoot at them through the roof of their car. Victoria Hand has even stated that Romanoff does not usually require extraction teams on S.H.I.E.L.D. missions and is resourceful enough to make her own escape.
Master Interrogator
Romanoff was able to trick Loki into telling her about his plan to use Hulk against the Helicarrier to bust him out of his cell. She was able to do a "reverse interrogation"; while she seemed to be in danger, in truth, she was getting all the information she wanted to know.
Expert Hacker
Romanoff can hack into most computer systems without tripping any firewalls or security. She used this talent to hack into Hammer Industries mainframe and help James Rhodes regain control of the War Machine Armor and enabled him to help Stark fight the rest of the attacking Hammer drones, and again to access the location of Camp Lehigh from the USB Steve Rogers received from Nick Fury.
Pilot
Romanoff is a skilled pilot, capable of flying a Quinjet with ease.