Mi camiseta lisa tiene una raya azul.

In Spanish, adjectives agree in gender and number with the noun they describe.

• camiseta is feminine and singular.
• The adjective liso (plain, smooth) must also be feminine and singular: lisa.

So:

• la camiseta lisa ✅
• el pantalón liso ✅
• la camiseta liso ❌ (gender mismatch)

Lisa can mean both smooth and plain, depending on context.

In the context of clothing, especially in Spain, camiseta lisa usually means:

• plain T‑shirt, i.e. without a pattern, design, or print.

It can also be understood as “smooth” (not textured), but when talking about clothes, learners can safely think of liso/lisa as “plain (no pattern)” in most everyday contexts.

In Spanish, the default position for descriptive adjectives is after the noun:

• camiseta lisa = plain T‑shirt
• camiseta roja = red T‑shirt
• coche nuevo = new car

Putting the adjective before (e.g. lisa camiseta) is possible but marked: it sounds poetic, very emphatic, or sometimes changes nuance. For normal speech, you should place lisa after camiseta.

In Spain:

• camiseta = T‑shirt, usually knit, short‑sleeved, casual, no buttons.
• camisa = shirt, usually with a collar, buttons, and often long sleeves (a dress shirt).

Example:

• Voy en camiseta. = I’m in a T‑shirt.
• Voy con camisa y corbata. = I’m wearing a shirt and tie.

In this context, raya means stripe.

Common meanings:

• una raya en la camiseta = a stripe on the shirt
• una raya en el suelo = a line on the floor
• la raya del pantalón = the crease in trousers
• rayo (different word) = a ray or bolt (e.g. of light, lightning)

So una raya azul is best translated here as a blue stripe.

Spanish adjective order is usually:

noun + descriptive adjective

• raya azul = blue stripe
• coche rojo = red car
• falda corta = short skirt

Azul raya is incorrect here; color adjectives almost always come after the noun.

Azul is an adjective that does not change for gender, but it does change for number.

• Singular: azul (masculine or feminine)
  • una raya azul
  • un coche azul
• Plural: azules
  • unas rayas azules
  • dos coches azules

So:

• una raya azul ✅
• unas rayas azules ✅
• una raya azula ❌

Tener means to have, so mi camiseta lisa tiene una raya azul literally says:

My plain T‑shirt has a blue stripe.

You use hay (“there is/there are”) when you talk about existence, not possession:

• Hay una raya azul en mi camiseta. = There is a blue stripe on my T‑shirt.

That’s also correct Spanish, but it focuses on the existence/location of the stripe, not on the T‑shirt “having” it. Both are possible; the sentence given chooses tiene.

Yes. In clothing contexts, llevar is very common:

• Mi camiseta lisa lleva una raya azul.

Here, llevar means something like “features” or “has as part of its design.”
Tener is also correct; llevar just sounds a bit more natural when describing details of clothes.

Not necessarily. Context decides:

• Camiseta lisa usually means “no pattern or print.”
• Having one simple stripe can still feel “plain” compared to very busy patterns.

However, if the stripe is a clear design feature, many speakers might avoid lisa and say simply:

• Mi camiseta tiene una raya azul.
• Mi camiseta es blanca con una raya azul.

So the sentence is grammatically fine; whether it sounds natural depends a bit on the exact design and how strict the speaker is about calling it “plain.”

Mi is a possessive adjective: my.

• mi camiseta = my T‑shirt
• la camiseta = the T‑shirt

In Spanish, it’s normal to use a possessive when you’d use my, your, etc. in English:

• Mi camiseta lisa tiene una raya azul. = My plain T‑shirt has a blue stripe.

Using la camiseta lisa tiene una raya azul would mean the plain T‑shirt has a blue stripe, with no explicit owner.