Skills

Skills are divided amongst the three categories of secondary attributes, which are physical, social, and mental. Though do note this division is largely for formatting and DM's who need to decide what characters roll. Also remember that any attribute can be rolled with any skill, so these lines are hardly final.
Similar to secondary attributes, skills are bought with EXP, but at a lower cost (3 x Newlevel) for each level. For example, if you want to upgrode from 0 to 3 in Medicine, you would first spend 3 EXP to go to skill 1, then 6 to go to skill 2 (total 9), then 9 to go to skill 3 (total 18).

Physical
Athletics, Your general ability to perform sports, be agile, and make the most out of your strength.

Stealth, Your ability to hide, stay quiet, and stay out of sight.

Thievery, Your ability to forge documents, pickpocket pedestrians, and slip illegal coin.

Melee, Your knowledge of where to hit, common melee form, and general melee capitalization.

Ranged, Your affinity to trajectories, aiming, safety practice, and broader ranged details.

Survival, Your knowhow of nature, the wilds, foraging, and how to survive.

Craft, Your handiness in creating weapons, ammo, armor, and other items of interest.

Social
Haggle, Your ability to play tone, spin narratives, and drive social situations to where you want them to be. This skill is primarily rolled during long social situations or during trade.

Insight, Your capability of reading tone, discerning body language, and seeing between the lines. This is used to gleam traits of people and to make martial checks during combat.

Subterfuge, Your ability to lie, manipulate, and scheme. This is rolled when trying to tell a lie, keep a lie, or spread rumors.

Streetwise, Your affinity with the more hidden cultures, the underworld, criminals, gangs. This can be rolled both to utilize criminal codes and to recall information on said groups.

Animals, Your aptitude for taming and communicating with animals.

Intimidation, Your ability to scare, threaten, or demoralize someone through various means.

Performance, Your ability to sing, play instruments, act, and generally perform to the public. This includes speeches and leader performances.

Mental
History, The ability to recall knowledge of previous events, situations, and history.

Medicine, A Characters knowledge of anatomy, the body, medical tools, and medical operations.

Arcana, General knowledge and affinity of magic, biomancy, and technomancy.

Awareness, The ability to see, hear, and generally sense hidden or hard to spot things.

Appraisal, The affinity towards currency, the value of items, and general economics.

Investigation, A Characters ability to connect the dots, follow papertrails, and find inner workings. While Awareness may find where the buttons lie, investigation provides clues onto which buttons you should press.

Engineering, Knowledge of construction, buildings, and structures, your architects for example.