The Greeks measure risk, not direction.

Delta measures how much an option's price is expected to move for a ₹1 move in the underlying. A call option has a delta between 0 and 1; a put has a delta between −1 and 0. A delta of 0.5 means the option's price moves roughly ₹0.50 for every ₹1 move in the underlying.

Delta is also commonly read as an approximate probability of the option expiring in the money — a 0.30 delta call is loosely read as roughly a 30% chance of finishing ITM, though this is an approximation, not an exact probability.

For traders running multiple options positions, position delta (the sum of each leg's delta, scaled by quantity and lot size) shows the net directional exposure of the whole book — a useful number for staying aware of how much the position behaves like being long or short the underlying itself.

Gamma measures how much delta itself changes for a ₹1 move in the underlying. It's highest for at-the-money options close to expiry, and lowest for deep in-the-money or out-of-the-money options.

High gamma means delta — and therefore the position's directional exposure — can change quickly as the underlying moves, which is why positions near expiry can feel like their risk profile shifts fast even without a large price move.

Sellers of options are typically short gamma, meaning their position works against them accelerating in the direction the market is already moving, which is a core reason options selling strategies require active risk management rather than a set-and-forget approach.

Theta measures how much an option's price is expected to decline per day, holding everything else constant. It's expressed as a negative number for long option positions — a theta of −5 means the option loses roughly ₹5 of value per day from time decay alone.

Theta decay isn't linear: it accelerates as expiry approaches, which is why options in their final week tend to lose value noticeably faster than the same option did a month earlier, all else equal.

Option buyers are fighting theta — the underlying needs to move enough, and fast enough, to outpace the daily decay. Option sellers collect theta as their edge, which is the basic mechanic behind most premium-selling strategies.

Vega measures how much an option's price changes for a 1 percentage-point change in implied volatility, with the underlying price held constant. A vega of 0.10 means the option gains or loses roughly ₹0.10 in value for each 1-point move in implied volatility.

Vega is highest for at-the-money options with more time to expiry, and falls as expiry approaches — which is part of why options can lose value into events even if the underlying doesn't move, if implied volatility drops sharply afterward (a pattern often called an IV crush).

Vega is the Greek most tied to market expectations rather than price action itself — it reflects how much movement the market is pricing in, not how much has actually happened.

Rho measures how much an option's price changes for a 1 percentage-point change in interest rates. Calls have positive rho and puts have negative rho, since higher rates modestly increase the value of the right to defer paying for the underlying (calls) and decrease the value of the right to defer receiving cash for it (puts).

Rho is the smallest of the five main Greeks in day-to-day impact for most short-dated options trading, since interest rates move slowly compared to price and volatility. It matters more for longer-dated options, where the time value affected by rates is larger.

In practice, most short-term options traders monitor delta, gamma, theta, and vega closely and treat rho as a background factor rather than an active risk to manage.