The Resultative Verb ติด
The word ติด primarily means "to stick" or "to be attached." Like many Thai verbs, it is frequently used as a resultative serial verb. Placed immediately after an action verb, it indicates that the action successfully resulted in a connection or attachment.
Phone Calls and Digital Connections
One of the most common ways you will hear ติด is with phone calls. When you dial a number, the goal is to connect. If the call goes through successfully, it is โทรติด. If the line is busy, dead, or lacks a signal, you negate the result rather than the action: โทรไม่ติด (cannot connect / won't go through).
This same logic applies to digital connections. For example, pairing it with the verb เชื่อม (to connect or link) works perfectly for pairing devices like Bluetooth.
Physical Sticking and Pasting
Naturally, ติด is also used for literal, physical attachment. When you use an action verb like แปะ (to paste), adding ติด confirms that the object successfully adhered to the surface. If an adhesive is worn out and fails to work, you say แปะไม่ติด (it won't stick).
You can also add the aspect marker ไว้ (for later) directly after ติด to indicate leaving something attached, such as a note on a message board.